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REEFKEEPERS FAQ: Water, Filtration, Lights, Cost (1/3)

( Part1 - Part2 - Part3 )
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See reader questions & answers on this topic! - Help others by sharing your knowledge
Reef Keepers Frequently Asked Questions  (Part 1 of 3)

Note: This header is copied into all three parts

(Well, more or less.  Actually, this is a composite document written
by many folks.  It contains information each participant felt was
basic information required for anyone considering maintaining a reef
tank.  In reality, it's turned into a bit of a reference document.
Some of the information has been taken from public forums like the
Internet UseNet *.aquaria groups.  Credit to the authors of such
information is given next to their contribution.)

Note that starting with 1.12, new and/or changed items are marked with
an "*" in the far left column.

*Release 1.12 - 17 Aug, 1994 (more corrections and minor area expansions)
Release 1.11 - 18 Apr, 1994 (some corrections and minor area expansions)
Release 1.10 - 9 Sep, 1993 (Significant additions to test kit and protein
                            skimming sections. Many spelling and grammar
                            corrections, some style and format alterations.)
Release 1.02 - September 1st, 1993    (Reorganized, split into 3 pieces)
Release 1.01 - July 1st, 1993     (First Public Release)
Release 1.00 - May 12th, 1993  
*Copyright 1993, 1994, ReefKeepers, All Rights Reserved

ReefKeepers, for purposes of the copyright, is the group of authors
listed at the end of this 3-part document.  Permission is granted for
it to be copied (unmodified) in either electronic or hardcopy form by
nonprofit organizations if it is copied in its entirety and used in
stand-alone form.  This document may not otherwise be published,
posted, uploaded, replicated or copied by any method, electronic or
physical, without the explicit permission of ALL of the listed
contributors.

The authors of this document have kindly spent the time to bring you
their opinions.  They are not liable in any form or fashion, nor are
their employers, for how you use this information.  Their opinions
should not be construed as fact; don't blame them if your tank has
problems.

You may get a copy of this FAQ via FTP from the following sites:

percula.acs.uci.edu (128.200.34.15)     /reefkeepers/faq
*ftp.cco.caltech.edu (131.215.48.151)    /pub/aquaria/FAQfiles/Reefkeepers

/---------------------------------------------------------------------------/

Table of Contents

Basic Sections:

Part 1)

1.0	Water (Filters/Additives/Test Kits)
	1.1 Source Water -  City Mains Water Is Not Good Enough
		1.1.1 Background
		1.1.2 DI Filters
		1.1.3 RO Filters
		1.1.4 Further Comments About Water
	1.2 Additives
	1.3 Testable Parameters
		1.3.1 Alkalinity
		1.3.2 Calcium
		1.3.3 pH
		1.3.4 Nitrate (NO3)
		1.3.5 Phosphate (PO4)
		1.3.6 Specific Gravity
	1.4 Water Changes
2.0  	Filtration and Equipment
	2.1 Live Rock
	2.2 Protein Skimmers
                2.2.1 Counter Current Air Driven Protein Skimmers
                2.2.2 Venturi Protein Skimmers
                2.2.3 Protein Skimmer Considerations
	2.3 Granular Activated Carbon (GAC)
	2.4 Other Chemical Filter Media (X-Whatever)
	2.5 Mechanical Filtration
	2.6 Under Gravel Filters (UGF)
	2.7 Reverse Flow UGFs (RUGF)
	2.8 Trickle Filters
	2.9 Algae Scrubbers (somewhat long)
	2.10 Live Sand
3.0	Lights
*	3.1 General Discussion
*	3.2 Detail Discussion
*	3.3 Lighting Data
4.0	Cost Estimates

Part 2)

5.0	Stock 
	5.1 Common to Scientific Name Cross Reference
	5.2 Coral Aggression Chart
	5.3 Corals [Cnidaria (Anthozoa)]
	5.4 Shelled Things
	5.5 Algae
	5.6 Possible Problems
*	5.7 Hermit Crabs

Part 3) 

6.0     General Catalogs
7.0     Questions and Answers
8.0     Book Review
9.0     Useful Tables
10.0    Credits

=========================================================================
1.0      Water

1.1      Source Water - City Mains Water Is Not Good Enough
   
1.1.1    Background

*   US EPA requirements for water quality from municipal sources are
    insufficiently pure for reef tank usage.  For instance, the EPA
    standard for Nitrate (as NO3-N) is 10.0 mg/l, over twice the
    recommended maximum level.  Extremely toxic (to inverts) heavy
    metals such as copper are allowed at levels as high as 1 mg/l.

    Most public water supplies have contaminates well below the EPA
    levels and some reef tanks have done fine on some public supplies.
    In general, however, it is recommended that some form of post
    processing be performed on public water before it is introduced
    into the reef tank.

    Although some people have access to distilled, de-ionized or
    reverse osmosis water from public sources, most will use a home
    sized system to produce their tank water.  The two most common
    systems used are de-ionization resins, and reverse osmosis
    membranes.

1.1.2	DI filters

    De-ionization (DI) units come in two basic varieties: mixed bed and
    separate bed.  Two chambers are used in separate bed units, one
    for anion resins (to filter negatively charged ions), the other
    for cation resins (to filter positively charged ions).  Mixed bed
    units use a single chamber with a mix of anion and cation resins.

    DI units are 100% water efficient with no waste water.  They are
    typically rated in terms of grains of capacity (a grain is 0.065
    grams).  Once the capacity of the unit is reached it either needs
    to be replaced or recharged (using strong acids and bases).
    Recharging is normally only an option for separate bed units.

    A quick check of the local water quality charts (normally
    available free from the water supply company) will reveal the
    water purification capacity of a given DI unit.  For example, if a
    unit rated at 1000 grains is purchased and the local water supply
    has a hardness of 123 mg/l (Missouri River, USA), then the unit
    capacity is (1000*0.065)/0.123 = 528 liters = 139.5 gallons of
    purified water.

    Water production rates for DI units varies, but is typically
    around 10-15 gallons/hour.

1.1.3	RO Filters

    Reverse osmosis (RO) units are normally based upon one of two
    membrane technologies: cellulose triacetate (CTA) and thin film
    composite (TFC).  CTA based systems are typically cheaper and do
    not filter as well (90-95% rejection rates).  TFC based systems
    cost more but have higher pollution rejection rates (95%-98%).
    CTA membranes break down over time due to bacterial attack whereas
    TFC membranes are more or less impervious to this.  CTA units are
    not recommended for reef tank purposes.

    RO filters work by forcing water under pressure against the
    membrane.  The membranes allow the small water molecules to pass
    through while rejecting most of the larger contaminates.

    RO units waste a lot of water.  The membrane usually has 4-6 times
    as much water passing by it as it allows though.  Unfortunately,
    the more water wasted, the better the membrane usually is at
    rejecting pollutants.  Also, higher waste water flows are usually
    associated with longer membrane life.  What this means in practice
    is that 300 gallons of total water may be required to produce 50
    gallons of purified water.
    
    Like any filter, RO membranes will eventually clog and need to be
    replaced.  Replacement membranes cost around $50-$100.  Prefilters
    are often placed in front of the membrane to help lengthen the
    lifetime.  These filters commonly consist of a micron sediment
    filter and a carbon block filter.  The micron filter removes large
    particles and the carbon filter removes chlorine, large organic
    molecules and some heavy metals.  Of course, the use of prefilters
    makes initial unit cost more expensive but they should pay for
    themselves in longer membrane life.

    RO units are rated in terms of gallons per day of output with
    10-50 gallon/day units typically available.  Note that the waste
    water produced by a RO unit is fine for hard water loving
    freshwater fish such as Rift Lake cichlids.  Some route the reject
    water to the family garden.

    The Spectapure brand of RO units has a good reputation.

1.1.4	Further Comments About Water

    The ultimate in home water purification comes from combining the
    two technologies and processing the water from an RO unit though a
    DI unit.  If a very high grade DI unit is used, water equivalent
    to triple distillation purification levels can be achieved.  Since
    the water entering the DI unit can be 50 times purer than
    tapwater, the DI unit can process 50 times as much before the
    resins are exhausted.  This significantly reduces the replacement
    or recharging cost of the DI unit.

    If only one filter can be afforded, and waste water is not a concern,
    then it is recommended that a TFC RO unit with pre-filters be purchased.
    If waste water is a concern, or if only a small quantity of make-up 
    water will be required (say, for a single 20 gallon tank), then a DI 
    unit would be the preferred choice.

    City water is unstable.  Many cities modify their treatment
    process several times a year, dramatically changing its
    suitability for reef usage.  For instance, Portland has great reef
    water - most, but not all, of the year.

1.2 	Additives

    Calcium (Ca) - required addition.  A range of 400-450 ppm Ca++ 
    (10-11 mM) is recommended.  The preferred method is the usage of 
    Kalkwasser (Limewater) for all evaporation make-up water.  The use 
    of Calcium Chloride (CaCl2) is known to cause problems with alkalinity 
    (provable by balancing the relavent chemical reactions occuring in the 
    tank when CaCl2 is added).  Still, CaCl2 is occassionally useful to
    repair serious Ca++ deficits.  

    Chelated calcium:

    The efficacy of chelated calcium products available for reef aquaria is
    questionable.  To the best of our knowledge, there exists no scientific
    evidence indicating that chelated calcium is especially available to 
    corals and other CaCO3 depositing invertebrates.  Nothing is known about
    the uptake of chelated calcium products by coral.  And most importantly, 
    there exists no evidence showing that chelated calcium products support 
    stony coral growth rates in excess of, or even *comparable to* growth
    rates documented in aquaria where calcium is supplied as aqueous Ca(OH)2
    [kalkwasser.]

    Chelated calcium products also interfere with the ability to measure
    actual calcium levels in the aquarium.  In particular, chelated calcium
    cannot be measured by any kit which uses EDTA titration, including the
    highly recommended HACH kit.  Some people find the SeaChem kit, which
    does measure chelated calcium, to be impossible to read with any 
    accuracy.

    Until such a time as vendors supplying chelated calcium products make
    available well conceived, carefully documented uptake and growth studies
    with their products, or the same experiments are performed and published
    by third parties, we regard the use of chelated calcium products in the 
    reef aquarium to be experimental at best, especially when kalkwasser 
    and other non-chelated calcium sources are KNOWN to us to support the 
    growth and even reproduction of stony corals in the home aquarium.

    Iodine (I) - enhances soft coral growth.  It is removed by
    skimming.

    Strontium (Sr) - used rapidly by most hard corals (weekly
    additions usually performed).

    Buffers - increase alkalinity and control pH. Desired range is
    2.5-3.5 meq/L (7-10 dKH) alkalinity.  Alkalinity can be raised by the 
    addition of one of many commercial buffer compounds.  The addition of
    kalkwasser (saturated Ca(OH)2 solution - also known as
    "limewater"), which is often done to maintain calcium levels, will
    also raise the alkalinity level.  SeaChem's Marine Buffer, Reef
    Builder and Kent's Superbuffer dKH are popular.  The Coralife and
    Thiel buffer products have had less favorable reviews.

    Iron (Fe) - Used by algaes.  Add this if you want good macroalgae
    growth.  Be sure that macroalgae growth is favored or else plague
    levels of hair algae may result.

    Copper (Cu) - Used as a medication in fish-only tanks.  Copper is
    highly toxic to invertebrates, even in very small concentrations.
    DO NOT USE THIS, IN ANY FORM, EVER, IN A REEF TANK OR ANY TANK
    WHICH CONTAINS INVERTEBRATES.  PERIOD!

    Other additives, especially the commercial "secret formula"
    mixtures, are more controversial.  Some people report good results
    from some of them other people report disaster or no effect.
    Experiment cautiously with them if desired.

1.3 	Testable Parameters

    Note: parts per million (ppm) and milligrams per liter (mg/l) are
    virtually identical in seawater and the units are used
    synonymously in this document.
  
1.3.1   Alkalinity 

    Alkalinity is a measure of the acid buffering capacity of a solution.
    That is, it is a measure of the ability of a solution to resist a
    decrease in pH when acids are added.  Since acids are
    normally produced by the biological action of the reef tank
    contents, alkalinity in a closed system has a natural tendency to
    go down.  Additives are used to keep it at a proper level.

    Correct alkalinity levels allow hard corals and coralline algae to
    properly secrete new skeletal material.  When alkalinity levels
    drop, the carbonate ions needed are not available and the process
    slows or stops.

    Alkalinity is measured in one of three units: milliequivalents per
    liter (meq/l), German degrees of hardness (dKH) or parts per
    million of calcium carbonate (ppm CaCO3).  Any of the units may be
    employed but dKH is most commonly used in the aquarium hobby and
    meq/l is used exclusively in modern scientific literature.  The
    conversion for the three units is:

            1 meq/l = 2.8 dKH = 50 ppm CaCO3

    [As an aside, there is an imperial unit of alkalinity and hardness
    which is 'grains per gallon'.  The water softening industry uses
    this unit.  1 gpg = 17 ppm CaCO3.]

    A word of caution about the ppm CaCO3 unit is in order. The 'ppm
    CaCO3' unit reports the concentration of CaCO3 in pure water that
    would provide the same buffering capacity as the water sample in
    question.  This does not mean the sample contains that much CaCO3.
    In fact, it tells you nothing about how much of the buffering is
    due to carbonates, it is only a measure of equivalency.

    Alkalinity is often confused with carbonate hardness since both
    participate in acid neutralization and test kits may express both
    in either of the three units.  However, carbonate hardness is
    technically a measure of only the carbonate species in equilibria
    whereas alkalinity measures the total acid binding ions present
    which may include sulfates, hydroxides, borates and others in
    addition to carbonates.  In natural seawater, though, carbonates
    make up 96% of the alkalinity so equating alkalinity with
    carbonate hardness isn't too far off.

    Recommended values for alkalinity vary depending on who's work you
    read.  Natural surface seawater has an alkalinity of about 2.4
    meq/l.  Following are levels recommended by various authors.

    From John Tullock (1991) "The Reef Tank Owner's Manual":
	page 46 - Alkalinity range should be 3.5 to 5.0 meq/l.
	page 94 - Alkalinity reading of 2.5-5.0 meq/l is proper.
	page 188- Alkalinity should be about 3.5 meq/l. (In reference
		  to maintaining Tridacna clams.)

    Albert Thiel (1989), in "Small Reef Aquarium Basics" recommends
    5.35-6.45 meq/l.  This is an artificially high level which may
    initiate a "snowstorm" of CaCO3 precipitate.  Most reef aquarists
    do not believe in such extreme and unnatural levels and recommend
    3.0-3.5 meq/l as a good range instead.

    The chemistry of how alkalinity, pH, CO2, carbonate, bicarbonate,
    and other ions interrelate is fairly complex and is beyond the
    scope and detail of this document.

    Some recommended test kits for alkalinity are the SeaTest kit and
    the LaMotte kit.  The SeaTest kit is very inexpensive and is one
*   of the few SeaTest kits suitable for reef use.  The SeaTest kit
    measures in division of 0.5 meq/l or, if the amount of solution is
    doubled, 0.25 meq/l.  The SeaTest kit uses titration in which the
    acid and indicator are included in the same reagent.  The LaMotte
    kit is a little more expensive, though still fairly cheap, and is
    somewhat more accurate.  The unit of titration is 4 ppm CaCO3
    although in practice, one drop from the titration tube may be up
    to twice this amount making the resolution about 0.15 meq/l.  The
    Lamotte kit has a separate indicator tablet and acid reagent which
    is a nice feature.

1.3.2   Calcium

    Calcium content is referred to as 'calcium hardness' and is
    measured either in parts per million of calcium ion (ppm Ca++) or
    parts per million equivalent calcium carbonate (ppm CaCO3).
    Calcium hardness is often confused with alkalinity and carbonate
    hardness since the 'ppm CaCO3' unit may be used for all three.  As
    with alkalinity, a calcium level expressed as X ppm CaCO3 does not
    imply that X ppm of calcium carbonate is present in the tank; it
    merely states that the sample contains an equivalent amount of
    calcium as if X ppm of CaCO3 were added to pure water.  The
    reading also does not tell you how much carbonate is present.

    Calcium hardness test kits are different from alkalinity kits.
    Some people have reported difficulties with the LaMotte calcium
    hardness kit.  The Hach 'Total Hardness and Calcium' kit has not
    had these reports.  Both express results in ppm CaCO3.  The
    relationship between CaCO3 and Ca++ is:

            1 ppm CaCO3 = 0.4 ppm Ca++

    The results from a test kit reading in ppm CaCO3 may be converted
    to the molar concentration scale by dividing by 100.

	    100 ppm CaCO3 = 1 mM Ca++
	     40 ppm Ca++  = 1 mM Ca++

    Calcium levels of natural surface seawater are around 420 ppm
    Ca++ (10.5 mM).  In a well running reef tank you will notice, sometimes
    dramatic, calcium depletion.  Calcium addition in some form is
    essential.  A calcium level above 400 ppm is required and a range
    of 400-450 ppm Ca++ is recommended.  Most reefkeeping books (see
    bibliography) explain the options for calcium addition.

1.3.3	pH

    The suggested reef tank range is 8.0 to 8.3.  The pH should hold
    its own unless alkalinity is low.  If alkalinity is OK but pH is
    low there is probably a buildup of organic acids or a serious lack
    of gas exchange (low water surface area to volume ratio).

1.3.4	Nitrate (NO3)

    Two units are used to measure nitrates: nitrate (NO3-) and nitrate
    nitrogen (NO3-N or just N).  The ratio is:

            1 ppm NO3-N = 4.4 ppm NO3-.

    Nitrates themselves may not be a problem but serve as an easily
    measured indicator of general water quality.  Many hard to test
    for compounds like dissolved organics tend to have levels that
    correlate well with nitrate levels in typical tanks.

    Different authors cite varying upper nitrate values permissible.
    No higher than 5 ppm NO3- is a good number with less than 0.25 ppm
    recommended.  Unpolluted seawater has nitrate values below
    detectable levels of hobbyist test kits, so "unmeasurable" is the
    goal to strive for.

    Most test kits measure nitrate-nitrogen.  Do not forget to
    multiply by 4.4 to get the ionic nitrate reading.  LaMotte makes a
    nitrate test kit that will measure down to 0.25 ppm NO3-N.  Hach
    makes one good to 0.02 ppm NO3-N, about 10x more sensitive, but
    you must be sure to order the saltwater reagents.  They will only
    sell you the saltwater reagents in addition to the regular kit
    with the freshwater reagents, not in place of them, which is
    annoying.  This makes the Hach kit about twice as expensive in the
    end as the LaMotte kit but the 10x increase in performance makes
    this more acceptable.

1.3.5	Phosphate (PO4)

    Phosphates, along with nitrates, are a primary nutrient of algae.
    Tanks with "high" levels of phosphates tend to be infested with
    hair algae.  All authors cite zero ppm PO4 as a good goal.  An
    upper level 0.1 ppm is recommended by Tullock (1991) with less
    than 0.05 ppm given by Thiel (1991).

1.3.6	Specific Gravity

* Short form:
*   Specific Gravity is temperature dependant.  See the next table for
*   a quick lookup of the recommended hydrometer readings.  They are
*   based upon our recommended S.G. of 1.025 at 60 degrees F.
*   
*Degrees F.	Hydrometer reading.
*   50                1.0255
*   55                1.0252
*   60		      1.0250
*   65		      1.0246
*   70		      1.0240
*   75		      1.0233
*   80      	      1.0226
*   85		      1.0218  (rather hot for most tanks)
*   90		      1.0210  (very hot for most tanks)
*
* In more detail:
*   1.025 recommended for reef tanks.  Note that virtually all hydrometers
*   are calibrated for measurements at a temperature of 60 F.  Included
*   below is a short table of temperature adjustments.  Add the value
*   shown to your hydrometer reading to get an accurate reading.
*
*Degrees F.	Correction
*   50           -0.0005
*   55           -0.0002
*   60		  0.0000
*   65		  0.0004
*   70		  0.0010
*   75		  0.0017
*   80      	  0.0024
*   85		  0.0032
*   90		  0.0040
*
*For example:  If the hydrometer reads 1.0235 at 80F, the actual
*	       Specific Gravity is 1.0235 + 0.0024 = 1.0259
*
*Note:	If your tank is between 75F and 80F, this means you should
*       try and keep your Specific Gravity around 1.0230 to 1.0235.
*
*For all practicle purposes, the scale is linear between data points,
*so you can simply extrapolate between table entrys.  For instance, 
*78F is 3/5 the distance between 75F and 80F; the difference in corrections
*is 0.0024-0.0017 = 0.0007.  3/5th of 0.0007 is 0.0004.  Add the offset
*0.0004 to the base value for 75F of 0.0017 and you get a correction
*value for 78F of 0.0021.
*
*It is fairly common in literature to see references to salinity in terms
*of Parts Per Thousand (PPT).  For salinities in the range we are interested
*in, the conversion formulas are:
*
*  Salinity = 1.1 + 1300 * (Temperature corrected Specific Gravity - 0.999)
*  Temperatur corrected Specific Gravity = ((Salinity - 1.1) / 1300) + 0.999;
*
*Here is a short table of some common values:
*
* Salinity	   Specific Gravity
*  20 PPT		1.0135
*  25 PPT		1.0174
*  30 PPT		1.0212
*  35 PPT		1.0251		* Typical Ocean Value * 
*  40 PPT		1.0289

1.4	Water Changes

    "The solution to pollution is dilution".  Water changes are used to
    correct problems.  Minimal changes of 5%/year when all is set up
    and running smoothly may suffice.  Some feel that an occasional
    water change of about 20% every 1-3 month is a reasonable safety
    net that may help prevent contaminate buildup and trace element
*   depletion problems.  Others recommend 5%-10% per week.

2.0	Filtration and Equipment

2.1	Live Rock

    Live rock is simply old coral skeletons that have become the home
    to multiple small creatures.  Typically reef tanks have 1-2 lbs of 
    live rock per gallon of capacity.  Pieces vary in size and shape
    from baseball size to dinner plate size in typical tanks.  In large
    tanks (> 500 gallons) very large pieces of live rock tend to be used.
    These pieces may individually weight up to 85lbs (about the limit of
    what one person can handle).  

    The use of live rock greatly increases the bio-diversity in a tank.
    However, its primary purpose is to provide a home for bacteria that
    provide the biological filtration for the aquarium.

    Cheap rock has low amounts of coralline algae and tends to grow
    hair algae well.  It may be suitable for a soft coral only tank.
    Hair algae free coralline encrusted live rock (high quality
    Florida and/or pacific (Marshall and Tonga Island) rock is highly
    desirable.  "Berlin" style tanks use high quality live rock (and
    protein skimming) as the primary filtration method with great
    success.
    
2.2	Protein Skimmers

    Required equipment.  Don't undersize.  Common wisdom is that you
    can't overskim a tank.  Many of the more available commercial
    units are useful for tanks only in the 10-20 gallon range.
    Anything shorter than about a foot tall is essentially useless.

    Unfortunetly, there is no formula to determine the required size
    of a skimmer.  Amount of organic waste generating organisms (fish,
    coral, live rock, etc.) will obviously be the primary variable.
    All skimmers should be filled with TINY bubbles and have a milky
    white appearance.  Any skimmer that doesn't match that requirement
    is not working optimally.

    Two basic styles of skimmers exist: counter current air driven and
    venturi driven.  Both styles work fine, both have tradeoffs.  Both
    require tuning.  Expect to spend some time over the first month or
    so learning how to keep your skimmer tuned.  Below is some
    discussion about the two styles.

2.2.1   Counter Current Air Driven Protein Skimmer

    These skimmers usually require three pieces of equipment typically
    not sold with them: an air pump, air stones and a water pump.
    Total skimmer cost depends upon the kinds of equipment needed to
    run the skimmer properly.

    The water pump injects the water to be skimmed into the unit.
    Some people use gravity to feed surface overflow water to the
    skimmer or divert part of the main circulation pump's return flow
    into the skimmer to eliminate the need for a dedicated pump.
    Otherwise a powerhead in the sump usually suffices for the water
    pump.

    The air pump must be large enough and a sufficient number of air
    stones must be driven to make the skimming column milky white.  In
    some skimmers one medium sized air pump like a Tetra Luft G and
    one air stone will be sufficient.  Other skimmers need more to
    perform optimally.

    Air driven skimmers should use limewood air stones which will need
    to be replaced from time to time.  Cheap limewood air stones have
    a reputation of needing to be replaced much more often than high
    quality stones.  Coralife limewood air stones have a good
    reputation.  Air stone replacement rate depends on your tank and
    skimmer; some people need to change them every 2 weeks others only
    after 3-4 months.

    A.J. Nilsen recommends a 1x tank volume per hour turnover of both
    water and air by counter current air driven skimmers.  Others feel
    each skimmer has an optimal rate of air and water processing and
    that if more skimming is desired then more or bigger skimmers
    should be added rather than trying to operate the current one
    beyond its optimal performance range.

    Some hold that any skimmer under 4' high and 4" in diameter is too
    small for anything over about a 20 gallon reef.

2.2.2   Venturi Protein Skimmers

    These skimmers use the Bernoulli effect of the venturi valve to
    inject air bubbles into the water.  This obviates the need of an
    air pump and air stones.  The penalty is that a relatively large,
    high pressure (read expensive and powerhungry) dedicated water
    pump is mandatory for the venturi unit to inject sufficient
    amounts of air.

    A particular commercial venturi skimmer may or may not come with a
    water pump.  If it does supply a pump, it may or may not be
    sufficiently large to run the skimmer properly.  At least some of
    the venturi skimmers easily available are not very well designed.

    Venturi valves require occasional cleaning of the air opening.
    This is as simple as reaming the opening out with pipe cleaner
    every few days.  An acid bath may be required if the unit clogs or
    gets coated with mineral deposits.

    Most venturi style skimmers are more compact that CC skimmers.
    Manufactures state that they are more efficient, since they
    (supposedly) inject more air.  Many suspect that design constaints
    (back pressure severely affects venturi performance) have more
    to do with the manufactured height (who would want a top injected
    4' skimmer with air only in the top foot of water?).  Properly
    designed venturi skimmers are tall to maximize air contact time,
    and require pumps that can handle backpressure.

2.2.3   Protein Skimmer Considerations

    Below are some pros and cons of venturi vs. CC skimmers.  Some
    people will debate some of the statements.

    Venturi skimmers, due to the large water pump needed, have a
    higher initial purchase price than CC units for the same amount of
    skimming.

    The operational cost of a venturi unit is basically just the
    electricity bill.  A CC unit must sum in electricity consumption
    for the water pump and air pump (usually small) plus air stone and
    diaphragm replacement.  Which one is more cost effective for you
    depends upon which equipment you had to buy to run the skimmer
    properly, your electricity rate and how often air stones need to
    be replaced.  Most people find CC skimmers less expensive to both
    purchase and operate for the same amount of skimming.

    Venturi skimmers are less cumbersome in appearance and in
    operation.  They are usually smaller and quieter.  They are on the
*   whole more hassle free.  The powerful pump required for venturi
*   skimmers may, however, add considerable heat to the water.

*   One general note on water pumps:  The amount of heat added to 
*   the water varies by brand, design, usage, and placement.  Basically,
*   the more efficient the pump (gallons delivered at a given pressure
*   for a given power usage), the cooler it will run.  Restricting
*   the output of the pump will generally increase the water temperature.
*   (Never restrict the intake of a centrifigal pump!) Obviously, an
*   air cooled pump will increase your tank temperature less than a
*   submersible (and therefore tank water cooled) pump will.

2.3       Granular Activated Carbon

    Some debate about its usage.  Most use it at least a few days a
    month, some continuously.  Many brands have problems with
    phosphate leaching.

2.4	Other Chemical Filter Media

    X-Nitrate, X-Phosphate, Polyfilters, Chemi-pure, etc. - probably
    not needed in established, balanced reef aquaria.  A prominent
    manufacturer of these materials was either unwilling or unable
    to supply capacities for removing the named compounds from
    seawater.  May cause adverse reactions in some inverts.

2.5	Mechanical filtration

    This is an area of interest currently being debated.  Originally
    the FAQ stated:

       Good idea to pre-filter skimmer water.  Floss works fine and is
       cheap and disposable.  Sponges work well, but require cleaning
       twice a week or so.  Natural sponges with a medium fine or fine
       pore size are recommended.  Some people don't use mechanical
       filtration, allowing detritus to settle in places for removal by
       siphoning.  Some of these people make dedicated "settling tanks"
       to trap debris in a convenient place.

    Julian Sprung suggests not pre-filtering skimmer water as skimmers
    will remove particulates (rather than trapping them as a pre-filter
    would do).  Spotte confirms this and terms this filtering mechanism
    as 'froth floatation'.

    Many members of the group of authors do not use mechanical filtration.
    They believe that such systems filter out the plankton that is used
    as food by many marine organisms.  Some members use "live sand" setups,
    with detrivores.  Others routinely siphon accumulated detritus.
    
    Use of a mechanical filter for short periods may help when attempting to
    resolve specific problems, such as a hair algae outbreak.

2.6	Under Gravel Filters (UGF)

    Not appropriate for a Reef Tank.  Although they will work for 6
    months or so, eventually detritus buildup will cause a nitrate
    problem.  Long term, it's virtually impossible to keep nitrates
    below about 40 ppm NO3- which is way too high for corals.
 
2.7	Reverse Flow UGFs

    An attempt to solve the detritus buildup problem associated with
    normal flow UGFs.  It's a good idea that doesn't work well in
    practice.  This system has problems with uneven water flow due to
    channeling within the bottom gravel.

2.8	Trickle Filters

    Also known as Wet/Dry Filters.  An improvement over UGF and RUGF
    filters.  Nitrates can be kept low (say, around 5 ppm) with
    adequate water changes.  It does not seem to be possible to keep
    nitrates very low (less than 1 ppm) if a trickle filter is the
    sole biological filtration.  Those that report less than 1 ppm
    normally have adequate live rock, and find that their Nitrates
    remain low even (and often get lower) when they remove all the
    bio-material from their trickle filters (turning them into plain
    sumps, useful for holding carbon and as a water reservoir).

2.9	Algae Scrubbers (long)

    Summary: the jury is still out.  May help, may hurt, not currently
    recommended, especially as the sole filter.  The topic is
    controversial.  Below is some discussion about it.

    In most healthy natural communities, particularly coral reefs,
    dissolved nutrients are scarce.  In aquaria, by contrast,
    nutrients in the form of dissolved inorganic nitrogen, or DIN, (a
    collective term for ammonia, nitrites, and nitrates) accumulate
    very rapidly as fish and other organisms excrete these wastes.
    The most basic problem in any aquarium is limiting the
    accumulation of DIN.

    In reef aquaria, DIN is consumed by the community of organisms on
    the live rock.  It is uncertain what relative contribution is made
    by bacteria as opposed to algaes, but it is certain that the live
    rock community as a whole can remove a substantial amount of DIN
    from a reef aquarium.  In fact, it is quite possible to run a reef
    tank with no biological filtration (DIN consumption) other than
    that which takes place on the rock.  This method is part of what
    is now known in the United States as the "Berlin school" of
    reefkeeping.

    Other schools of thought utilize additional biological filtration
    in separate filters.  Traditional reef tanks supplement the
    filtration provided by the reef (often not acknowledging the role
    of the reef itself) with bacteria-based trickle filters.  Many
    readers probably learned this technique first, as it has been the
    dominant method in the United States amateur hobby for some time.
    Yet another approach uses algaes, which are also capable of
    utilizing inorganic nitrogen directly.  An algae filter, or algal
    scrubber as it is usually called, is simply a biological filter
    which utilizes a colony of algae rather than bacteria as consumers
    of inorganic nitrogen.

    Algal scrubbers are not new; they are discussed in Martin Moe's
    (1989) excellent _Marine Aquarium Reference: Systems and
    Invertebrates_, for example.  However, algae filters have been
    regarded in the past as too bulky and inefficient to be the sole
    filter for a aquarium.  The recent surge of interest in algal
    scrubbers seems to have been generated by Adey and Loveland's book
    _Dynamic Aquaria_ (1991).  They discuss both techniques which
    allow an algal scrubber to be compact and efficient and also a
    number of arguments as to why they are preferable to other
    filtration methods.

    One reason to use an algal scrubber according to Adey and Loveland
    is that it mirrors the way DIN is cycled in nature.  They claim
    that perhaps 70-90% of the DIN in reef communities is consumed by
    algae, rather than by bacteria.  The two methods produce rather
    different water chemistry; for example, algae are net producers of
    oxygen and remove carbon dioxide, while a bacterial filter
    consumes oxygen and produces carbon dioxide.  They argue that it
    should be easier to maintain the type of water chemistry found
    over a natural reef by relying on an algal scrubber.

    Also, algae remove the nitrogen from the water in order to build
    tissue, while filter bacteria simply put it into a less toxic
    form.  The excess nitrogen can be removed completely by periodic
    algae harvests, while dissolved nitrogen in the form of nitrate is
    not as easy to remove. Adey and Loveland claim that their methods
    can bring levels of DIN down to a few hundredths of a ppm, far
    below (in their opinion) the levels reachable with other methods.
    A related argument in favor of algal scrubbers is that stability
    in natural ecosystems seems to come from locking up nutrients in
    biomass, not in allowing it to be free in the environment.  An
    algal scrubber does precisely this, while a bacterial filter
    converts it to free nitrate dissolved in the water.

    A final reason to use an algal scrubber according to Adey and
    Loveland is that many other kinds of filtration (including protein
    skimmers) remove plankton from the water. An algal filter
    naturally does not do this, and can actually provide a refuge for
    some forms of plankton.  The importance of this effect is,
    however, a matter of some debate.

    As compelling as some find the above arguments in theory, there
    seem to be serious problems with algal scrubbing in practice.
    Many attempts by public aquaria at implementing reef tanks using
    only algal scrubbing have been failures.  In particular, it seems
    difficult to find successful long term success with Scleractinia
    (stony corals) in such tanks, and those success stories which can
    be found are quite difficult to verify and often contradicted by
    others.

    Various public and private aquaria have used algae scrubber
    filters on their reef aquaria, with disastrous results. The
    microcosm at the Smithsonain Institution has yet to keep
    scleractinia alive for more than a year. While Dr. Adey has stated
    how well corals grow in this system, those viewing the system have
    failed to find these corals. In an interview with Jill Johnson,
    one of the techs responsible for the Smithsonian tank, she stated
    to Frank M. Greco that frequent collecting trips were needed to
    keep the system stocked with live scleractinia.

    The Pittsburgh AquaZoo also has a "reef" tank based on Dr. Adey's
    algal scrubbers.  This tank is nothing more than a pile of rocks
    covered with filimentous green algae, and the water is QUITE
    yellow (as is the Smithsonian tank) from the presence of dissolved
    organics (ORP readings have been around 165). As with the
    Smithsonian tank, scleractinia do not survive longer than a few
    months. The same applies to soft corals as well. When I (Frank M.
    Greco) saw this tank on May 3, 1993, there were NO living corals
    to be found even though a collecting trip to Belize was made
    several months earlier and 81 pieces of living scleractinia were
    brought back.  There were, however, two piles of dead Atlantic
    scleractinia: one right behind the tank and the other in the
    greenhouse housing the algal scrubbers.

    The Carnegie Science Museum (Pittsburgh, PA) also uses an algal
    scrubber system, but with significant modifications.  This tank
    looks the best of the three.  There are several species of hardy
    Scleractinia and soft corals that are doing quite well.  The water
    is clear (a bit cloudy). The major differences between this system
    and the other two is the use of carbon, a small, barely
    functioning algal scrubber, about 1000 lbs. of excellent quality
    live rock (Florida), water changes, and the addition of Sr and Ca.

    The last system I know of that uses an algal scrubber is the Great
    Barrier Reef Microcosm in Townsville, Australia. As of this
    writing, the system is not maintaining live Scleractinia, and
    frequent collecting trips are needed in order to replenish the
    exhibit. It should also be noted here that while Dr. Adey has
    claimed in his book Dynamic Aquaria that corals have spawned in
    this system, what he doesn't mention is that the corals which
    spawned were collected only months before the known spawning
    season. From these few examples, it should be clear that algal
    scrubbers are NOT to be used in systems containing live
    scleractinia.

    Possible reasons why algal scrubbers seem to fall short center
    around the observation that it seems difficult to control hair
    algae growth in scrubbed aquaria.  Hobbyists have for many years
    seen their stony corals slowly pushed back off of their skeleton
    and killed by encroaching algaes, and much effort in the hobby has
    been devoted to controlling this growth. Only with strict control
    of algaes does coral survival seem possible.  Most or all reefs
    with algal scrubbers seem to have heavy algal growth in the tank
    as well, which the experience of the hobby suggests is
    incompatible with stony coral survival.

    The main method used by hobbyists to restrict algal growth is to
    reduce nutrient availability; in fact, the claim that other
    methods cannot reach the same low levels of DIN achieved by algal
    scrubbing is probably not true.  Advanced hobbyists are beginning
    to use better tests, such as HACH's low level nitrate test, and
    are finding that they can achieve nitrate levels below 0.02 ppm.
    Berlin methods seem particularly able to reach these levels, which
    are comparable to that on natural coral reefs.

    If low nutrient levels can be achieved by both methods, then why
    is algal growth a much greater problem with scrubber methods?  The
    answer is not known, but there are two factors which probably
    contribute.

    First, the discussion so far has mentioned only inorganic
    nitrogen. Algaes seem to release much of the inorganic nitrogen
    which they take up in the form of dissolved organic compounds
    (DON), which can also be later utilized by algaes.  The very low
    levels of DIN measured in scrubbed tanks may mask the very high
    levels of DON which persist, providing nutrients for strong algal
    growth.  This is borne out by many reports that the water in
    scrubbed tanks often has a pronounced yellow cast, characteristic
    of dissolved organic compounds.  Since the water over natural
    reefs is very low in DON, high levels may be directly harmful to
    many corals, in addition to promoting uncontrolled algal growth.

    Another possible effect of algal scrubbing is more subtle.  Algal
    growth is never completely halted in any marine tank, merely
    reduced to the point where macro- and micrograzers can keep them
    in close check.  The net rate of new growth depends not only on
    the availability of nutrients, but also on the amount of existing
    algal growth releasing free-floating cells into the water to
    colonize new sites.  Even if the rate of growth of individual
    algal colonies is equal, a scrubbed tank has a growth of algae in
    the scrubber much larger than a reef tank with little algal growth
    anywhere in the system.  This possibility suggests that the
    presence of the scrubber itself and not merely high levels of DON
    is an obstacle to the successful long-term maintenance of stony
    corals.

    The weight of evidence at this point seems to be against the use
    of algal scrubbing in reef tanks, and the method should be
    considered to be highly experimental.  Beginners particularly are
    advised to avoid this technique until they have considerably more
    experience with reefkeeping. The advanced aquarist may well wish
    to experiment with this interesting and controversial method, but
    it would be unwise to risk the lives of an entire reef tank full
    of coral.  Such experiments should progress slowly, beginning with
    the most hardy of inhabitants.  Many of the objections center on
    stony coral survival, and it is possible that scrubbed tanks with
    fish and hardy invertebrates may do quite well.

2.10 Live Sand

    Of relatively recent interest in the hobby is the use of "live sand".
    Live sand consist of small grain (0.5mm-1.0mm) coral sand that is
    populated with crustations and bacteria.  It is normally used at a
    rate of 10lbs per square foot of bottom area - which yields about a
    1" deep covering.  Variations from 1/8" to 3"s of covering have been
    reported.

    If you decide to have a live sand substrate bottom, you should 
    include several creatures that will turn-over, or otherwise, move
    the sand around.  Recommendations include: Sea Cucumbers, Brittle
    Starfish, Serpant Starfish, Golden Headed Sleeper Gobies, Yellow
    Jawfish, Watchman Gobies, and other detrivoirs.  A mix of the above 
    is recommended, since each creature moves the sand around differently.

    Live sand has a reputation of eliminating the final traces of nitrates
    in otherwise well run tanks.  It also provides an environment for 
    additional bio-diversity in the tank.  Additionally, some feel that
    the chemical balance and stability of a tank's water is improved when
    live sand is present.

*   Note that live sand usage should still be considered experimental.
*   Usage is dependant upon have the sand sifted and otherwise moved
*   around to prevent detritus from accumulating.  Many people have reported
*   problems keeping their turn-over creatures alive for long periods
*   of time.  Some have not seen the reported nitrate reductions.  Keep
*   in mind that many reef tanks have operated for years without a substrate
*   and have no detectable nitrate concentrations.

3.0	Lights

*3.1	General Discussion

    A rough "rule of thumb" is 4 Watts/gallon with successful tanks
    using from 1.5 - 6 Watts/gallon.
 
    1) Fluorescent fine (some prefer) for shallow (<20") tanks.  Use
    mix of bulbs (50-50, 03s, etc.)

    2) Metal Halide (MH) required for deeper tanks.

    3) Mercury Vapor, Halogen, HPS, etc. - avoid, wrong spectral
    output.

*3.2	Detail Discussion

    For most aquarium lighting applications, the bottom line is
    getting the needed intensity and spectrum of light at the lowest
    cost while remaining within aesthetic limits.

    A lighting analysis is now presented.  Everyone has their own sets
    of numbers they would plug in here, for now lets assume the
    following for comparison.  Many will debate specifics found below.
    Feel free to substitute your own numbers, but the methodology is
    sound.

    Bulb cost and performance:

	NO lumens per lamp	= 2600 (Phillips F40D daylight, initial)
	NO watts per lamp	= 40 (ditto)
	NO cost per lamp	= ~$20 (from memory, DLS actinic day)

	VHO lumens per lamp	= 5940 (Phillips F48T12/D/VHO daylight, initial
)
	VHO watts per lamp	= 110 (ditto)
	VHO cost per lamp	= ~$30 (ditto)

	MH lumens per lamp	= 36000 (Philips MH400/U, initial)
	MH watts per lamp	= 400 (ditto)
	MH cost per lamp	= ~$70 (from memory, Venture 5200K)

	operate lamps 12 hours/day
	replace lamps once per year
	electricity cost	= $.09 / KWH (your mileage may vary)

    Annual cost per lumen:

	cost = ( cost-per-lamp / lumens-per-lamp )
	     + ( watts-per-lamp / lumens-per-lamp ) * 12 * 365 * .09 / 1000

	NO cost  = .0077 + .0061 = .0138 dollars per year per lumen
	VHO cost = .0051 + .0073 = .0124 dollars per year per lumen
	MH cost  = .0019 + .0044 = .0063 dollars per year per lumen

    Basically, in fluorescents, the VHO lamps give a higher operating
    cost but a lower replacement cost for the same total amount of
    light.  But it's close, and you should plug in your own numbers to
    see what's best for you.  If you replace lamps more frequently
    then VHO is better, if you pay more for power, NO is better.

    There is a greater variety of lamps available for NO than VHO.
    OTOH, it seems that NO lamps can be operated at VHO power levels,
    with a somewhat shortened lifetime (the higher replacement
    frequency is offset by lower lamp cost), so this may not be an
    issue.

    The initial installation cost (basically the ballast cost) is
    higher for VHO, even in terms of per-lumen, but this is a pretty
    small part of the total cost of the lighting system over the
    years.

    NO requires more lamps for a given total light intensity, so you
    may not be able to fit enough NO bulbs in your hood if you need a
    lot of light.

    MH seems to be a winner in both replacement and operating costs,
    but there are a couple of caveats.  The math ignores the effect of
    the ballasts on power consumption, whereas I've measured
    fluorescent power consumption as less than the lamp wattage (even
    on conventional transformer ballasts) and MH power consumption as
    slightly higher than the lamp wattage.  The other caveat is just
    the EXTREMELY limited choice of spectrums for MH, which is why few
    people use MH without any fluorescent.

    MH vs fluorescent also gets into the aesthetic and biological
    considerations.  Water surface ripples causing light ripples in
    the aquarium and room are pronounced with MH lighting.  Many
    people appreciate this effect.  Some (e.g. Julian Sprung) feel the
    variation in light intensity is actually important for some
    photosynthetic organisms.

    Many people are under the impression MH runs hot, whereas
    fluorescent doesn't.  In reality, the efficiencies are similar,
    with MH producing slightly LESS heat than the equivalent
    fluorescent.  The difference is MH dumps all the heat in a small
    space so the local temperature rise is greater.  But if you want
    to try to get rid of the heat it's actually easier to do it if the
    heat is concentrated in one spot, since its easier to get rid of a
    small amount of very hot air than a very large amount of warm air.

    A separate issue, so far only applicable to fluorescent, is the
    selection of a conventional ballast vs an electronic one. There is
    no doubt the electronic ones are more expensive to purchase, but
    the savings in electricity offset the high initial cost in a year
    or so.  Also, if heat production is an issue, the electronic
    ballasts are to be favored.  The Icecap VHO electronic ballast is
    widely advertised, however its advertised claims are also
    frequently questioned.  Advance makes a series of NO electronic
    ballasts.

    There are yet two more issues, for which there are a lot of
    questions and too few answers.  Specifically, the short term
    flicker in light intensity, and radiated electromagnetic fields.

    Fluorescent lamps on conventional ballasts flicker at 120 Hz,
    which is above the human visual response, so we don't see it
    (actually, the flicker is both in intensity and spectrum).  But
    that doesn't mean other creatures can't see it, or whether they
    benefit or are disadvantaged by it.  Electronic ballasts cause
    flicker at ~30 KHz; it is seriously doubtful that any creature can
    detect this, so it would appear constant.

    The flicker doesn't have to be visible to have an effect: it
    causes any movement to appear strobed, and this may affect the
    feeding efficiency of visual hunters.

    The fields issue is even more obscure.  At least many
    cartilaginous fish (sharks, rays, etc) are known to be extremely
    sensitive to electric fields, and many crustaceans are sensitive
    to magnetic fields (crabs with pieces of magnetite in internal
    sensory organs).  Fluorescent lamps, with the large area they
    cover, tend to radiate (using the term pretty loosely) fairly
    strongly, but MH, and the wiring, and the ballasts can radiate
    too.  It's unknown on how significant this could be in an aquarium
    (but its known sharks preferentially attack undersea cables
    because of the fields, so there is at least indirect evidence its
    an issue worth some thought).

    BTW, a grounding device reduces the level of induced voltages in
    the tank, but this is achieved at the expense of increased induced
    current, so its effect (if any) may depend on the species.  Also,
    note if you have a titanium coil chiller on the tank, it is probably 
    already grounded through the chiller, and an additional ground may in 
    fact increase the electric current.  This should not be an issue
    with epoxy or ceramic coated chiller coils.

*3.3	Lighting Data (whole section new, and copyrighted!)

==========================================================================
FILE|WATTS|MANUFACTURER|DESCRIPTION      |HOURS      |TYPE      |
T1   400   IWASAKI      6500K                          M/H
T2    20   LIGHTSOURCE  UVB                            FL
T3    20   LIGHTSOURCE  UVB WITH FILTER                FL
T4   400   VENTURE      4000K                          M/H
T5   400   VENTURE      4000K WITH FILTER              M/H
T6   400   SYLVANIA     4000K             2400 HOURS   M/H
T7    60   CHROMALUX                                   TUNGSTEN
T8    40   CORALIFE     50/50                          FL
T9    40   ACTINIC SUN                                 FL
T10   40   PHILLIPS     ACTINIC 03        3650 HOURS   FL
T11   40   PHILLIPS     ACTINIC 03                     FL
T12   40   RAINBOW      PRIMETINIC                     FL
T13   40   RAINBOW      FLORA_GLOW                     FL
T14   40   RAINBOW      BIO_LUME                       FL
T15   40   TRITON                         3650 HOURS   FL
T16   40   DURALIFE     POWER TWIST                    FL
T17   40   HAMILTON     SUPER ACTINIC     3650 HOURS   FL
T18   40   PKILLIPS     ULTRALUME         3650 HOURS   FL
T19   40   PERFECTO     PERFECTALIGHT                  FL
T20   40   SYLVANIA     350EL BLACKLIGHT  3650 HOURS   FL
T21   40   SYLVANIA     350EL BLACKLIGHT               FL

nm	T1	T2	T3	T4	T5	T6	T7	T8	T9
280		0	0						
290		0.00369	0						
300		0.01136	0						
310		0.0173	0						
320		0.01326	0						
330		0.00725	0						
340		0.00366	0						
350	0.00928	0.00126	0	0.00173	0	0.01344	0.00156	0	0
360	0.01185	0.00155	0	0.03944	0	0.07642	0.00071	0.00012	0.00011
370	0.02	0.00199	0	0.03428	0	0.07363	0.00166	0.00115	0.00104
380	0.03036	0.0007	0	0.0043	0	0.03063	0.00361	0.00086	0.00075
390	0.0446	0.00084	0	0.01287	0	0.05199	0.00574	0.00422	0.00329
400	0.07903	0.00544	0.0014	0.07214	0.01949	0.14805	0.01098	0.02255	0.01686
410	0.08931	0.0058	0.00188	0.06103	0.02356	0.1331	0.01644	0.05968	0.04407
420	0.16201	0.00126	0.00076	0.01713	0.01747	0.06811	0.02291	0.08731	0.06047
430	0.09997	0.01352	0.01175	0.13073	0.13383	0.2202	0.02654	0.09023	0.06469
440	0.08765	0.02331	0.02023	0.1601	0.1598	0.2264	0.03179	0.0736	0.05465
450	0.07976	0.00053	0.00041	0.01077	0.01184	0.04449	0.03795	0.02631	0.02099
460	0.12665	0.00078	0.00072	0.00687	0.00716	0.03796	0.04864	0.01588	0.01347
470	0.15064	0.00074	0.00069	0.01622	0.02078	0.07935	0.06293	0.01061	0.00931
480	0.16282	0.00071	0.00066	0.01501	0.01751	0.07474	0.08342	0.01361	0.0122
490	0.262	0.00081	0.00075	0.01746	0.01798	0.07031	0.10565	0.02889	0.02518
500	0.1875	0.00074	0.00069	0.01715	0.01926	0.07363	0.11878	0.01326	0.01125
510	0.1742			0.03241	0.03973	0.12924	0.11684	0.00561	0.00456
520	0.1746			0.01067	0.01085	0.06063	0.11877	0.00424	0.00337
530	0.1903			0.01495	0.01622	0.06525	0.11566	0.00658	0.00568
540	0.2163			0.2472	0.2453	0.3389	0.17133	0.0945	0.08678
550	0.2249			0.3589	0.3569	0.4931	0.2222	0.10093	0.08811
560	0.1535			0.01939	0.02075	0.07519	0.2276	0.00777	0.00829
570	0.1721			0.15115	0.15653	0.2859	0.11034	0.00485	0.00444
580	0.2015			0.4783	0.47	0.6035	0.04333	0.02203	0.0205
590	0.11089			0.1499	0.10326	0.4279	0.04889	0.02291	0.02103
600	0.13418			0.015	0.01253	0.07882	0.15686	0.01332	0.01218
610	0.12794			0.01226	0.01103	0.0517	0.2926	0.07374	0.06906
620	0.14258			0.02842	0.0302	0.10766	0.3906	0.04382	0.03969
630	0.13358			0.03349	0.03673	0.10084	0.4227	0.02397	0.02217
640	0.11311			0.014	0.01398	0.05127	0.4511	0.00603	0.00571
650	0.09402			0.01115	0.01077	0.04064	0.4742	0.00692	0.00652
660	0.10513			0.01143	0.01088	0.04971	0.4899	0.00584	0.00544
670	0.085			0.01551	0.01315	0.08427	0.4922	0.00403	0.00386
680	0.08657			0.01111	0.01079	0.03203	0.4808	0.0037	0.00358
690	0.09202			0.01929	0.01898	0.03834	0.4944	0.00411	0.00377
700	0.08359			0.00975	0.01033	0.03056	0.5355	0.00286	0.00277
710	0.04801			0.01305	0.01273	0.02949	0.5522	0.00911	0.00917
720	0.05045			0.01045	0.01025	0.03059	0.5485	0.00149	0.0014
730	0.04745			0.00957	0.00941	0.0182	0.4476	0.00042	0.0004
740	0.04609			0.00985	0.00964	0.02177	0.2395	0.00041	0.00039
750	0.04023			0.00983	0.00959	0.01954	0.2498	0.00037	0.00035

nm	T10	T11	T12	T13	T14	T15	T16	T17	T18
350	0	0	0.0001	0	0	0	0	0	0.00011
360	0	0	0.00167	0	0	0	0.00144	0	0.00147
370	0	0.00016	0.00087	0.00119	0.00126	0.00145	0.00196	0	0.00133
380	0.00011	0.0007	0.00063	0.00027	0.00017	0.00023	0.00145	0.00011	0.0007
390	0.00403	0.00563	0.00399	0.00033	0.00012	0.00018	0.0021	0.00155	0.00066
400	0.01468	0.0379	0.02569	0.00377	0.00299	0.0037	0.00745	0.02094	0.00546
410	0.04403	0.12285	0.07521	0.00446	0.00432	0.00611	0.00952	0.08984	0.0083
420	0.06681	0.1955	0.12078	0.00138	0.00651	0.00983	0.0078	0.15751	0.00904
430	0.06231	0.1714	0.13584	0.01281	0.03371	0.03597	0.02406	0.14212	0.03191
440	0.04237	0.10573	0.1221	0.0229	0.0599	0.05814	0.03307	0.08825	0.04797
450	0.01287	0.03535	0.05784	0.00225	0.04818	0.04703	0.0128	0.03013	0.02376
460	0.00567	0.01538	0.03935	0.00271	0.04462	0.05381	0.01496	0.01326	0.02429
470	0.00268	0.00698	0.02608	0.00332	0.03433	0.0541	0.01834	0.0061	0.02294
480	0.00125	0.00319	0.02679	0.00396	0.02981	0.05097	0.02108	0.00287	0.03173
490	0.00082	0.00195	0.05095	0.00486	0.03909	0.04972	0.02354	0.00178	0.05773
500	0.00062	0.00051	0.02319	0.00537	0.02092	0.03006	0.02579	0.00056	0.02643
510	0.00037	0.00073	0.00728	0.00672	0.01013	0.01802	0.02974	0.00079	0.01024
520	0.0003	0.00056	0.00496	0.00985	0.00732	0.01111	0.03445	0.00064	0.0078
530	0.00027	0.00049	0.00645	0.016	0.00668	0.01075	0.03592	0.00056	0.013
540	0.00623	0.01053	0.13192	0.03586	0.07958	0.0697	0.04315	0.00846	0.1921
550	0.01079	0.0185	0.1251	0.05488	0.07655	0.06983	0.04723	0.01463	0.1743
560	0.00028	0.00038	0.01025	0.04627	0.00731	0.0088	0.02902	0.00035	0.02394
570	0.00061	0.00085	0.00549	0.05201	0.00444	0.00586	0.02876	0.00069	0.01534
580	0.00314	0.00569	0.03686	0.0556	0.02172	0.0227	0.032	0.00446	0.04439
590	0.00039	0.00047	0.03892	0.04418	0.01716	0.02913	0.02544	0.00044	0.04907
600	0.00013	0.00051	0.01518	0.04409	0.00375	0.02508	0.0284	0.00036	0.03261
610	0.00126	0.00136	0.09569	0.04722	0.01159	0.16014	0.03433	0.00087	0.14292
620	0.0009	0.0015	0.06356	0.05247	0.04658	0.07106	0.03533	0.0013	0.08503
630	0.00057	0.00087	0.0269	0.06004	0.06313	0.03852	0.03461	0.00084	0.04806
640	0.0003	0.0006	0.00674	0.05213	0.05384	0.0087	0.03259	0.00043	0.01323
650	0.00025	0.00047	0.00797	0.07652	0.1192	0.01039	0.0305	0.00036	0.01485
660	0.00026	0.00049	0.00564	0.10016	0.1775	0.00799	0.02782	0.00039	0.01222
670	0.00023	0.00043	0.00554	0.04559	0.06493	0.00461	0.02474	0.00035	0.00851
680	0.0002	0.00039	0.00499	0.02232	0.01908	0.00396	0.02155	0.00031	0.00761
690	0.00032	0.00056	0.00425	0.01701	0.00976	0.00639	0.01861	0.00047	0.00787
700	0.00022	0.00041	0.00348	0.01193	0.00434	0.00551	0.01536	0.00032	0.00583
710	0.00041	0.00077	0.01145	0.00964	0.00302	0.01905	0.01322	0.0006	0.01719
720	0.00022	0.00049	0.00167	0.00712	0.0013	0.00286	0.01038	0.00034	0.00305
730	0	0.00013	0.00044	0.00546	0.00072	0.00068	0.00827	0	0.00054
740	0	0.00012	0.00045	0.0044	0.00059	0.00075	0.00685	0	0.00098
750	0	0.00013	0.0004	0.00352	0.00045	0.00071	0.00559	0	0.00093

nm	T19	T20	T21						
300			0						
310			0.01441						
320			0.00473
330			0.01484
340			0.03041
350	0	0.01513	0.02693
360	0.0001	0.01831	0.03403
370	0.00144	0.01491	0.02582
380	0.00097	0.00948	0.01617
390	0.00474	0.0052	0.00903
400	0.00806	0.00633	0.00942
410	0.01157	0.00532	0.00778
420	0.01243	0.00154	0.00258
430	0.02928	0.01093	0.01555
440	0.0403	0.01854	0.02698
450	0.0223	0.00053	0.00163
460	0.0258	0.00069	0.00137
470	0.02929	0.00061	0.00124
480	0.03084	0.00057	0.00072
490	0.03039	0.00076	0.00119
500	0.02779	0.00063	0.00101
510	0.02431	0.00037	0.0007
520	0.02064	0.00029	0.00056
530	0.01756	0.00028	0.00048
540	0.02217	0.00924	0.00974
550	0.02535	0.01594	0.01769
560	0.00816	0.00029	0.00033
570	0.00725	0.00062	0.00081
580	0.0119	0.00497	0.00639
590	0.00888	0.00044	0.00042
600	0.00953	0.00035	0.00037
610	0.05257	0.00111	0.00114
620	0.03046	0.00129	0.00145
630	0.03244	0.00082	0.00089
640	0.02281	0.00047	0.00047
650	0.04607	0.00035	0.00037
660	0.06831	0.00039	0.00038
670	0.02469	0.00033	0.00034
680	0.00813	0.0003	0.0003
690	0.00567	0.00046	0.00047
700	0.00362	0.00031	0.00032
710	0.0071	0.00062	
720	0.00146	0.00033	
730	0.00059	0	
740	0.00052	0	
750	0.00045	0	

ALL DATA CONTAINED WITHIN IS COPTRIGHT 1994 BY FRANK M. GRECO
(phrank2139@aol.com) AND BRUCE ROBERTS (baldbruce@aol.com) AND TO BE USED
ONLY WITH PERMISSION OF ONE OR BOTH OF THESE PEOPLE.
=========================================================================

4.0	Cost Estimates

    Here is a rough estimate of what setting up a reef tank may cost.
    Two cases are included: a 20g micro-reef and a 70g mini-reef.  The
    estimates show the min and max for most of the common pieces of
    equipment.  The estimates assume a standard type of filtration
    that is popular today.  If a different setup is used, the price
    could be more or less.  The equipment includes a tank with some
    sort of siphon/drain to a sump and then a return pump back to the
    tank.  A protein skimmer is installed in the sump.  This setup is
    similar to a typical wet/dry trickle filter except there is no
    trickle section with media.  This allows the use of simpler, less
    expensive sump although a commercial W/D without media could be
    used. A trickle media could be utilized at greater cost although
    many reefkeepers think it is unnecessary.  Keep in mind that
    prices sometimes vary geographically.  Also, availability may
    vary.  For example, reasonable Florida live rock may soon no
    longer be available (at least not for $2-4/lb).

    The estimates include the cost of the initial set-up.  There is
    also a section on ongoing costs.  The ongoing cost will vary
    greatly, especially considering that you will stock your tank
    gradually.  Keep in mind that you always end up spending more than
    you think you will. If you set up a reef, you will end up stopping
    at the hardware store and/or aquarium store for timers, extensions
    cords, GFIs (a must!), buckets, hoses, and books, don't for forget
    books.  You should read a few books on reefkeeping before even
    planning your setup.  An extra hundred bucks or three _is_ going
    to leak out of your wallet whether you plan on it or not.

    Another factor is that more advanced equipment may translate into
    less or easier maintenance.  You should keep in mind that if you
    go with inferior equipment, maintaining the tank will be more
    work.  More expense will mean more automated equipment and less
    work.  Also, some varieties of inverts require more exacting
    condition, more light, etc.  Plan your purchases so that the stock
    you buy has a chance of surviving with the equipment you are
    using.  If you have a bare minimum system, stick hardy items like
    soft-corals, polyps, mushrooms, etc.

    The minimum included is close to rock-bottom as far as an
    acceptable systems goes.  It assumes that you are DIYing much of
    the equipment as cheaply as possible.  The maximum in the estimate
    is in some areas a little extravagant but not unreasonable. A good
    system that is not extravagant could be put together for somewhere
    in between the two extremes.  Perhaps, for 1.25 to 2 times the
    minimum, you would have a very nice system.  Some areas are easier
    to cut-corners on than others and some of the initial cost may be
    incremental, like buying test kits as needed.  Also, you may have
    some of the equipment already from previous set-ups or be buying
    it used. Seek out the advice of an experienced reefkeeper when
    planning and pricing your system.

-------------------------------Micro-Reef(20g)-------------------------------
Tank		$  20/ 140	Glass/
				Acrylic.
Stand               0/ 250	Sturdy piece of furniture/
                                Fancy acrylic stand.
Lights            100/ 300      DIY 60W fluorescent/
				70W or 150W MH hood or pendant.
Main Pump          20/  60      Large powerhead/
				Hobby pump.
Sump		   10/ 120      A plastic storage container from the
				hardware store / A small commercial W/D
				without media.  (A nice DIY acrylic
				sump can be built for about $40.)
Skimmer            60/ 220      DIY skimmer, power head, air pump/
				Small commercial venturi unit with
				integral pump.		
Plumbing           30/ 100      DIY overflow and misc pipes, etc/
				Drilled tank or commercial overflow box
				plus misc pipes, etc.
Live-Rock	  140/ 400	35lb case of Fla rock plus shipping/
				30lbs of Pacific rock plus shipping.
Water Treatment	  100/ 600      DIY mixed-bed DI with carbon prefilter/
				TFC RO unit with DI postfilter and 
				automated top-off.
Test Kits    	  100/ 500      A SW combo kit plus and Alk and Ca test/
				Most of the Lamotte and/or Hach kits
                 		you think you might need.
Salt		   10/  20      One 50g bag, price varies.
Accessories	   20/ 200      There are a variety of gadgets you could
				get.  You might want to start with a
				net or two and maybe a pair of tongs.
		 ---- ----
Setup Total	$ 610 2910

--------------------------------Mini-Reef(70g)-------------------------------
	
Tank		$ 140/ 350 	Glass/
				Acrylic.
Stand		  100/ 500      Cheap wood or iron stand/ 
p				Fancy acrylic stand.
Lights		  200/ 600      DIY 160W fluorescent/
				2x150-175 MH hood (possibly with Actinics).
Main Pump          80/ 140      400-600gph, price varies with brand.
Sump		   10/ 200      A plastic storage container from the
				hardware store / a commercial W/D
				without media.  A nice DIY acrylic
				sump can be built for about $50.
Skimmer    	   80/ 450      A DIY skimmer,powerhead,air pump/
				A large commercial venturi unit
				with a large pump driving it.
Plumbing           50/ 150      DIY overflow and misc pipes, etc/
				Drilled tank or commercial overflow box
				plus misc pipes, etc.
Live-Rock    	  460/1200      140lbs Fla rock plus shipping/
 				110lbs Pacific rock plus shipping.
Water Treatment	  100/ 600      DIY mixed-bed DI with carbon prefilter/
				TFC RO unit with mixed-bed DI
				postfilter and automated top-off.
Test Kits    	  100/ 500      A SW combo kit plus and Alk and Ca test/
				Most of the Lamotte and/or Hach kits
                 		you think you might need.
Salt		   20/  40      Two 50g bags, price varies.
Accessories	   40/ 500      There are a variety of gadgets you could
				get.  You might want to start with a
				net or two and maybe a pair of tongs.
				You could get wave-makers, circulation
				pumps and lots of other do-dads.
Chiller		    0/ 600      Don't use a chiller, live somewhere cool,
				keep the tank in the basement, or an
				adequately air-conditioned room/
				A commercial chiller.
		 ---- ----
Setup-Total	 1380 5830

--------------------------------Ongoing Costs---------------------------------

Additives- Most reefkeepers believe that some additives are necessary.
	At minimum, a buffer compound is needed to maintain the alkalinity.
	Also, some Calcium supplement such as Kalkwasser or Cacl2 should
	be used.  A few trace additives like Strontium and Iodine/Iodide
	should also be added.  The initial supply of these products will
	be around $50.  The ongoing rate will vary depending on the size
	of the tank.

Water Purifier- If you go with a DI system, you will have to replace
	and/or recharge resin.  An RO system will require periodic
	replacement of the membrane.  In the long run, maintenance
	of the RO is likely cheaper.

Test Kits Reagents- You will need replace reagents for the tests kits.
	Also, the minimum given above is may not be adequate.  The
	typical SW combo kits are not of low enough range for reef work.
	They will only be of use during the first few weeks of 
	cycling/curing.  That estimate assume that you will acquire
	the better tests over time or have access to someone else's
	expensive tests should you need to diagnose a problem.

Electricity- You will need it to run the pumps and lights.  It won't be
	insignificant.  Electric costs vary.  Check the KW cost
	on your electric bill.  Add up wattage of all the equipment you 
	are using, pumps 24hrs/day, lights 12hrs/day.  Calculate what
	the electricity will cost.  Don't forget cooling, in many areas, 
	you will need either a chiller or will have to air-condition the 
	room where the reef is kept.  The lights will generate heat.  At 
	minimum, your AC bill will also go up accordingly.  Electricity 
	mini-reef system could easily be a couple hundred bucks a year.

Water-	In some areas, water is expensive.  RO units waste several times 
	what they produce in water.  This could	add a little more expense.

Salt-   You may want to do water changes in which case you will 
*	eventually need more salt.   Salt mixes run $10-$25 per 50 gallon
*	mix.

Lights- Fluorescent tubes and MH bulbs wear out.  Fluorescent tubes
	are usually okay for nine months to a year before spectrum
	shifts and/output reduced significantly.  Some tubes, like
	actinics, may need replacement as frequently as every six 
	months.  Replacement MH bulbs is recommended about every one to
	two years (depending upon spectral shift and output degradation).
	Add up the cost of your tubes and figure in the
	replacement cost based on the estimated lifetime.

Stocking- This can really vary.  You probably shouldn't have more 
	than a couple fish in the micro-reef and not more than
	a handful in the mini-reef.  The typical fish suitable
	for a reef will be from $10(small goby or blenny) to
	$30(small angel or tang).  You could spend $300 on one purple
	tang though.  Pieces of coral, decorative rocks, giant
	clams and other sessile inverts start at around $20 a piece
	and go to many hundreds a piece.  Snails range from about
	$1/each to about $8/each and are recommended for controlling	
	algae.  Other motive inverts likes shrimp range from about
	$10 to $30.

	You probably should start with the snails as soon as the 
	live rock is in the tank.  You don't have to have any fish
	if you don't want any.  You don't have to have inverts either
	although that is probably why you set up a reef tank. Just 
	quality live-rock is very of nice to look at but sooner	or 
	later you will likely want something else in your tank.  The 
	invert stocking will be very incremental and should be.
	It is not heathly to add a lot of stock at once.  You can 
	spread you stocking over up to several years.  You could spend
	anywhere from say $100 to $750 on the micro-reef and $200 to 
	$10,000 on the mini-reef.

=================== End of ReefKeepers FAQ Part 1 of 3 =======================

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