Marine Aquarium Systems

Robert Rose

March 10, 2000

 

Abstract

 

In previous manuals on the creation and maintenance of a marine aquariums little emphasis is placed on the science of keeping marine animals: the chemical reactions, the nitrogen cycle, disease prevention and control, proper nutrient levels, and the many other factors that are involved in keeping marine creatures alive and healthy.  In this manual the author provides just that: a scientific approach to creation and maintenance of a marine aquarium.

 

0.1 Introduction

 

If you ask anyone who has ever kept marine animals if they enjoyed it, they will most always respond with a very positive “YES!”  Marine animals themselves offer an intriguing level of complexity not found in any other pet†.  Keeping marine animals can be an extremely rewarding experience—if the time is taken to learn how to do it right.

 

This manual is intended to give the novice or experienced marine animal keeper the proper background necessary to set up your first marine tank, or to learn more about the one you already have.  Within this manual you’ll find:

 

 

0.2 How to Use This Manual

 

Section 1, “Marine Tank Basics,” covers the bare essentials of every marine tank: seawater and animals!  Section 2, “Marine Tank Creation,” covers the equipment that go into your tank, (filters, heaters, etc.), and has instructions on how to assemble your first tank.

 

This manual is not designed to be read from front to back.  If you are a beginner, start in Section 1 and read the sub-section on Seawater, then skip to Section 2 and read about the gear you need to buy for your first tank.  Once you have your tank set up, go back to Section 1 and read about what kind of fish to put in it.

 

An important note to the reader: This manual should not be treated as a “complete” guide to keeping marine animals.  There are many factors involved when keeping marine animals, and although this manual may cover most of them, it does even come close to covering all of them.  To be successful with marine animals you must constantly be learning more about your marine creatures and their habitat.  Don’t stop learning after you read this manual!

 

Section 1: Marine Aquarium Basics

 

1.1 Seawater

 

Water, as most of us have learned, is H2O, two Hydrogen atoms bonded to a single Oxygen atom.  H2O by itself is an extremely “sticky” molecule, in the sense that it likes to cling onto other molecules†.  This stickiness is what allows you dissolve substances in H2O.  When you stir sugar into a hot cup of tea, the sugar appears to disappear because the H2O separates and clings onto very small portions of the sugar.  When you dissolve something in H2O it is said to be in “solution.”

 

Seawater is a very complex solution.  Substances such as salt, manganates, carbonates, sulfates, nitrates, and many others are present in seawater.  In fact, there are so many substances in solution in seawater that the water itself (H2O), makes up only 96% of its content3!  A partial listing of natural seawater’s content is provided in Table 1.

 

Because seawater is the basic element in a marine animal’s livelihood, (for obvious reasons), the marine hobbyist must attempt to provide the highest quality seawater for his or her marine animals.  In the following sub-sections I will explain the elements of seawater that the marine animal keeper must be aware of.

 

Element

Species

mg/L

mol/L

H

H2O

108,000

1.07E2

O

H2O, O2

     857,000

5.36E1

Cl

Cl-

19,000

5.36E-1

Na

Na+

10,500

4.57E-1

Mg

Mg2+

1,350

5.55E-2

S

SO42-, NaSO4-

855

2.76E-2

Ca

Ca2+

400

9.98E-3

K

K+

380

9.72E-3

C

HCO3-, CO32-, CO2

28

2.33E-3

N

N2, NO3-, NO2-, NH4+, NH3

15

1.07E-3

Br

Br-

65

8.14E-4

B

B(OH)3, B(OH)4-

4.6

4.26E-4

Si

Si(OH)4

3.0

1.07E-4

 

Table 1: A Partial Listing of the Inorganic Composition of Seawater3

 

1.1.1 Salinity and Specific Gravity

 

The largest substance in seawater, (besides water!), is NaCl (sodium chloride or table salt).  When NaCl is dissolved in H2O it is broken up into it’s essential components Na and Cl, and a NaCl solution is said to be formed.

 

Marine animals expect a certain level of NaCl to be present in their water.  This level is commonly referred to as the “salinity” of the water.  Salinity by itself is a very difficult thing to measure because of all the other things that are present in seawater along with NaCl.  Instead, we measure the specific gravity.  Specific gravity is very closely tied to salinity, and is a lot easier to measure.

 

To measure specific gravity you will most often use a “specific gravity meter” or a conventional hydrometer.  Hydrometers are a little bit more difficult to use because they depend on the temperature of the water2.  For this reason I recommend you use a specific gravity meter.

 

An acceptable specific gravity for seawater is between 1.020 and 1.024, depending upon where you are in the ocean1.  For your marine tank, it is advised that you keep your specific gravity absolutely no lower than 1.020, and absolutely no higher than 1.025, preferably around 1.022.

 

Fish and other marine animals are extremely sensitive to changes in specific gravity because they depend on it to maintain their internal osmotic pressure2.  For this reason check your specific gravity on a regular basis (every week or so), and do water changes if necessary to restore your specific gravity back to normal.  If drastic specific gravity changes are required (more than .004), do it over a long period of time (1-2 days).

 

1.1.2 Alkalinity

 

The substances discussed above that are dissolved in seawater alter the properties of the water besides just changing the specific gravity.  The substances can also alter the Alkalinity and Acidity of the water.  Natural seawater is alkaline.

 

Alkalinity, by a purely chemical definition, refers to the concentration of OH- ions present in water3.  Dissolving a “basic” substance in the water creates these ions.  The reasons behind seawater being alkaline is beyond the scope of this text, so unfortunately I’ll just have to leave the reader with this: “Make sure your seawater is the right alkalinity.”

 

Fish and other marine animals are used to a steady alkalinity of 8.2pH5.  You can easily measure this within 0.1pH using a simple pH test kit available at your local fish store.  If your pH is too high, you can use a pH lowering product, and visa-versa.  Just remember to make these changes very gently over a long period of time.  Sudden changes in pH can kill your animals.

 

Note: If you are having trouble with your alkalinity, try doing a 10-25% water change before you run out and buy pH altering chemicals.  Doing water changes is a lot safer, and need to be done anyways!

 

1.1.3 Temperature

 

In the ocean, temperature can vary anywhere between 75ºF and 82ºF.  For a marine aquarium, it is recommended you keep your tank at a steady 78ºF1.  You can easily monitor your tank’s temperature using either a stick-on type thermometer that you affix to the exterior of your tank, or a floating thermometer.  The floating type is usually more accurate.

 

Sudden jumps in temperature, more than 2ºF in one hour, can be very stressful to your fish and other animals.  If you are having problems keeping your temperature steady, consider purchasing a better heating or cooling system.  (Heaters and chillers are discussed in Section 2).

 

1.1.4 Nitrification and Cycling

 

Seawater goes through a complex waste recycling process commonly referred to as the “nitrogen cycle” or nitrification.  During nitrification organic waste is decomposed into several different Nitrogen-based molecules by special sets of bacteria and other live organisms.  In the marine aquarium it is tricky to strike a balance with nitrification, and the marine aquarist must pay special attention to its maintenance.

 

 

 

Nitrification begins with organic waste: waste produced by plants, fish, etc.  Over a brief period of time (1-10 hours), this waste is naturally dissolved into the seawater.  One of the molecules that appear as a result of the dissolution is Ammonia, NH4.  Anaerobic bacteria then break down the Ammonia into Nitrite, NO2-, and finally into Nitrate, NO3-.  This process is outlined in Figure 1.

 

When you first set up your marine tank it takes about 25-30 days for the nitrification cycle to strike balance after you first put fish in it.  In the mean time you can observe sharp increases in your Ammonia, Nitrite, and Nitrate levels.  These early days of your tank are commonly called the “cycling” period.  (See Figure 2).

 

During cycling extra care and consideration must be put into your tank.  Check Ammonia and Nitrite levels regularly to make sure they rise and then fall back down.  Do not put any organism in your tank that can be sensitive to high concentrations of Ammonia or Nitrite (see “Fish,” section 1.2).  All invertebrates are extremely sensitive to Ammonia, Nitrite, and Nitrate, so they are out of the question during cycling.

 

When cycling is complete it is essential you perform a 25-30% water change with your tank.  After the water change Ammonia and Nitrite should be virtually non-detectable due to nitrification.  Check Ammonia and Nitrite levels regularly.  If you ever detect Ammonia or Nitrite after the cycling process is complete, do a 25-30% water change, and re-evaluate your filtration setup.  (See “Filtration” in Section 2).

 

After cycling, your Nitrate level will continually rise.  There is no way to naturally combat Nitrate in a closed system unless you are willing to deal with the only organism that eats Nitrate—algae.  (Algae has it’s own set of problems associated with it, and is not pleasant to look at, so we will not consider it as an option).  In a marine tank, you must frequently perform water changes, 10% every week, and regularly monitor Nitrate, in order to keep your Nitrate levels down.

 

 

Ammonia, Nitrite, and Nitrate, as you have probably guessed by now, are bad for marine animals.  Any of these substances in high quantities can ruin an otherwise healthy tank.  It is good practice to regularly monitor them and perform water changes as needed.  See Table 2 for a listing of acceptable Ammonia, Nitrite, and Nitrate levels.

 

 

Chemical \ Application

Fish Only Tank

Invertebrate Tank

Ammonia

< 1ppm

0ppm

Nitrite

< 1ppm

0ppm

Nitrate

< 10ppm

< 0.5ppm

 

Table 2: Acceptable Levels of Ammonia, Nitrite, and Nitrates (Parts Per Million)

 

 

1.2 Fish

 

In this sub-section I’ll cover popular fish for the beginner, and some fish the beginner should stay away from.  For an almost complete guide to picking fish for your marine aquarium see The Tropical Marine Fish Survival Manual in the reference section.

 

1.2.1 Damsels

 

Damsels are the perfect fish for the beginner.  These fish are very hardy, and can withstand the stress of tank cycling very easily.  Damsels are not very picky eaters either; they will eat most flake foods, (but still love an occasional frozen brine shrimp treat).  Best of all, damsels are very cheap!

 

The downside to damsels is that they can be very aggressive, especially males.  Damsels have a tendency to guard territory they believe is theirs, and challenge other fish for food.  Fortunately damsels rarely manage to damage any other fish, as they don’t have any teeth, so their aggressiveness plays off as more harassment than it does fighting.

 

Despite their aggressiveness damsels are still a good pick for the beginner.  In a large tank (55 gallons), 3-4 damsels won’t be too bad.

 

 

 

 

1.2.2 Mollies

 

Mollies are a freshwater fish that you can acclimate into saltwater.  Some people prefer to cycle their tanks with mollies because they are so much cheaper than regular saltwater fish.  Although this may be a less-threatening way to get started with your marine tank, your author does not recommend this method.

 

If you do decide to start your tank with mollies, you can acclimate them to saltwater by slowly increasing the salinity in their environment over a 6-8 hour period5.  Bear in mind that if you decide to get any real saltwater fish later they will never cease harassing the passive mollies.

 

1.2.3 Clownfish

 

Clownfish are not recommended for cycling a tank if you are a beginner, even though they are a fairly hardy fish.  Once your tank is done cycling, however, these are a great fish to add to your tank.

 

Clownfish can be very territorial towards non-clownfish, so pick your species carefully if you decide to get clownfish.  Ask your pet storeowner for compatibility.

 

1.2.4 Triggerfish

 

Triggerfish, (Huma-huma, Black Trigger, Bursa Trigger, etc), can be used to cycle a tank if done cautiously.  Triggerfish can be very aggressive sometimes, (as they are carnivorous), so be careful if you decide to setup a tank with triggerfish.  A general rule of thumb is to never place a fish smaller than a triggerfish in the tank with it, if you want to keep it!

 

1.2.5 Blennies and Gobies

 

Small fish in the Blenny and Goby class are very passive, however they are not hardy enough to withstand the cycling process.  Add these small fish to your tank once it’s done cycling.

 

A word of caution: Some species of Gobies are extremely picky eaters, especially the Mandarin and Dragonet Goby.  They are not recommended for the beginner.

 

1.2.6 Tangs

 

Tangs, or Surgeonfish, are hardy, fairly passive, and algae-eaters.  If no algae is present in your tank you need to feed them leafy green plants like lettuce to keep them fed.

 

1.2.7 Fish to Avoid

 

If you are a beginner, you must immediately walk away from Angels, Butterflies, Pipefish, Seahorses, Filefish, Mandarin Gobies, Dragonet Gobies, and Eels, and distrust any pet storeowner that tells you otherwise.  Use common sense, if a fish has a highly specialized diet (or if you don’t even know what it’s diet is), then stay away from it.

 

When picking out fish in the pet store, you also want to stay away from fish that look sick, are too shy, or would potentially cause harm to any other fish or animals you have in your tank already.  To test if a fish is a good buy, have the pet store owner try and feed it.  If it takes too long to notice food or is completely uninterested in it, then chances are it’s going to be difficult to feed or is sick.

 

1.3 Invertebrates

 

No invertebrate can withstand the cycling process in a marine tank.  Do not add invertebrates during cycling!

 

1.3.1 Shrimp

 

Shrimp are your author’s favorite invertebrate.  They can be extremely interesting to watch, and are fairly hardy.  Shrimp eat whatever falls to the bottom of your tank, and, in addition, spend most of their day grazing on algae and whatever else is growing in your tank.  For this reason it’s not a good idea to add Shrimp to your tank until it’s established (2-3 months).

 

Shrimps can occasionally require a high concentration of calcium in your tank in order to molt.  Check your calcium levels regularly to make sure they are between 400-450ppm.  Calcium depletion can be caused by poor nutrition, so feed your tank a variety of foods.

 

1.3.2 Crabs

 

Crabs are another invertebrate that can be interesting to watch.  Like shrimp, they’ll eat whatever falls to your tank.  They also have the same calcium requirement.  In addition, crabs require places to hide while molting, as bigger tank associates can harass them.  Never disturb a crab while it is molting!

 

Crabs are also very social.  It’s a good idea when you decide to purchase crabs to get them all about the same size and in groups of at least 3 or more.

 

 

 

 

1.3.3 Sea Anemones and Starfish

 

Sea anemones and starfish are not recommended for the beginner.  Both species are extremely sensitive to nitrate levels higher than 0.5ppm, and have special lighting requirements.  Sea anemones rarely flourish in non-reef tank setups.

 

Section 2: Marine Aquarium Creation

 

2.1 Marine Tank Equipment

 

2.1.1 The Tank

 

The tank is the most important part of your marine system, as it is the container, and will probably be with you for some time.  When purchasing a tank keep quality in mind.  Do not buy a tank with any chips or scratches in it, as they may lead to leaks later.  Stay away from tanks made of plastic or metal, as they may wear out or corrode over time.  (Corrosion can kill your marine creatures).

 

Consideration for space and weight requirements of your tank should also be taken.  Marine tanks can be very heavy.  30 gallons of water alone weighs about 500 pounds.  Your marine tank is not something you’re going to be able to move once you set it up!  In terms of space, your tank should not be placed in any drafty areas of your house, in direct sunlight, or near doors that frequently slam.

 

If you are new to marine animal keeping, purchase the largest tank you can afford.  This may sound ludicrous, but the more water volume you have the more forgiving your tank is going to be if you screw something up.  Do not purchase a tank smaller than 30 gallons for your first marine setup.  55 gallons is the optimum for beginners.

 

If you are experienced in marine tanks, and are thinking about getting a new one, think about gas exchange.  The majority of gas exchange in a marine tank takes place on the surface, so more surface area on the top of your tank will lead to a better gas exchange.  It’s for this reason that you primarily see really long marine tanks for sale.

 

2.1.2 Filtration

 

Many different options exist in the marine world for filtering and recycling water in your marine setup.  In the following sub-sections I’ll cover the most popular.

 

2.1.2.1 UGF and RUGF

 

The under-gravel filter (UGF) is probably the most widely used and popular system for filtration in a marine aquarium.  The process is simple: Water gets pulled downward in the tank through a substrate of some sort at the bottom, then gets sucked up through a set of tubes at the back of the tank, the released at the top.  Either a bubbler placed in the tube or a tiny pump called a “powerhead” causes this suction and pulling.  (See Figure 3).

 

 

The opposite of the UGF is the RUGF, the reverse under-gravel filter.  In the RUGF water gets sucked in through a powerhead and then pushed down the tubes and back out into the tank through the substrate.  RUGF’s overall are more effective methods of filtration than UGF’s because they prevent sediment from gathering above the substrate.

 

With both the UGF and RUGF 2-3” of substrate must be used.  In marine setups, it is recommended that you use a ground coral substrate because it provides more surface area than standard gravel.  Sand is quickly becoming a popular substitute for coral gravel, however it’s effectiveness in filtering is unproven, so sand is not recommended for the beginner.

 

UGF’s and RUGF’s require a regular substrate cleaning about once a month.  Using a siphon and gravel cleaner, stir up your substrate and suck out some of the “bad stuff” that accumulates.  Replace seawater as necessary afterwards.

 

Note: If you are not doing a UGF or RUGF system, have no more than .5” of substrate at the bottom of your tank, as it can lead to dead spots.

 

2.1.2.2 Wet-Dry Filters

 

Wet-Dry filters are another popular filtration method.  Wet-Dry’s work by pulling water out of your tank (by means of a water pump or siphon), then dripping it through a dry filter material.  The drips are collected in a sump and get pumped back into your tank.  The principle is that within the dry material there is a better gas exchange for bacteria to process organic waste.

 

Wet-Dry filters unfortunately can be either extremely effective, or disappointingly ineffective.  If you are considering purchasing a wet-dry filter (most good ones are more than $150), do some research and ask a lot of questions before you invest your money.

 

2.1.2.3 Protein Skimmers

 

Protein skimmers are essential if you are using a UGF or RUGF for your primary filtration and wish to have any delicate animals.  Protein skimmers are a vertical tube that is either placed inside your tank or is pumped to externally.  Inside this tube a dense stream of bubbles is created that clings onto organic waste and forms a foam at the top of the tube.  An overflow container at the top of the tube catches the foam, and then is disposed of on a regular basis.  This process is known as foam fractionation.

 

Protein skimmers are advantageous because they prevent a portion (60-90%, depending upon on the model) of organic waste from going through nitrification.  Less organic waste going through nitrification means lower nitrate levels, less algae growth, and a healthy habitat for your animals.

 

If you are considering invertebrates for your tank, a protein skimmer is essential.

 

2.1.2.4 Piggyback Filters

 

Piggyback filters hang onto the back of your tank and suck water out using a weak pump, then let water fall back into the tank after going through a filtering material.  Piggyback filters are effective in a marine environment, however they are not cost effective enough to justify purchasing one.  If you own one already, it won’t hurt to add it to you tank, but I wouldn’t suggest you purchase a new one.

 

2.1.3 Temperature Control

 

As mentioned in Section 1, fish like a temperature of about 78ºF.  Maintaining this temperature is important.  To do so you can use a variety of different types of heating and chilling units available for aquariums.

 

Hang-on type heaters are the most widely available type of heater, are the easiest to install and adjust, but lose accuracy if your water level changes.  Submersible heaters offer greater accuracy, but are more difficult to adjust.  Pick whichever heater is right for you.

 

There are a wide variety of chilling units available on the market, do proper research before you decide on one.

 

When purchasing a heater or chiller, make sure it contains absolutely no metal!  Metal can corrode in saltwater and poison your animals.

 

2.1.4 Lighting

 

Most marine animals you’ll put into your tank live close to the equator and in less than 50 feet of water2.  This means that they’re used to about a 14 hours of high-intensity light a day.  It is crucial to your fish’s health that this cycle be recreated in the aquarium using a light timer.

 

If your marine tank is going to contain only fish, the rule of thumb is to have one fluorescent bulb per foot depth of water5.  Do not use standard fluorescent bulbs.  Wide-spectrum bulbs are available at most fish stores for use in a fish tank.

 

Invertebrates require significantly more light than fish.  If you are considering invertebrates you will need to have at least two fluorescent bulbs per foot of water, where about half of your bulbs are high-spectrum “actinic” bulbs.

 

Another good way to light invertebrate tanks is using a metal-halide bulb system.  Metal-halide bulbs offer an even wider spectrum of light than fluorescent, but cost a lot more.

 

2.1.5 Rocks and Accessories

 

Fish need a place to hide, a place to swim and play, and rocks help create both.  When setting up your tank be sure to stack up lots of rocks.  Rocks are also an additional surface area for algae to grow, (which is important, because without it, nitrate levels would rise).

 

You may have heard of something called “live rock”.  Live rock is nothing more than regular rock that has microorganisms growing in it.  Putting some live rock in your tank early during cycling process is a good idea, as it increases the levels of healthy bacteria and gets your tank through the cycling process faster.

 

Many other accessories are available for your marine tank at your local fish store.  Before you add anything unnatural to your tank it’s a good idea to soak it in water and a few drops of chlorine for 2-3 hours, then allow it to dry for about a week before you add it to your tank.  This will prevent any dangerous bacteria or chemicals from getting into your tank.

 

2.2 Construction of Your Tank

 

So you have read all about marine aquariums, and now you’re ready to setup your first!  You should have all of the following things ready when you go to assemble your tank:

 

 

Once you have everything you need schedule about 2 hours of free time to perform the steps below:

 

1.    Take your tank and place it on top of its stand, or whatever else you’re going to put it on.  Make sure that the tank fits nice and snug.  There should be no wobbling or potential of tipping.  If the tank or stand wobbles, you might be able to fix the wobbling with a few sheets of paper slipped under the tank on the corners.

2.    If you are doing a UGF or RUGF filtration system, place the “gravel stand” at the bottom of the tank and connect all of the tubing and powerheads.  (Do not turn on the powerheads yet).

3.    Fill the bottom of the tank with substrate.  If you are doing a UGF or RUGF filtration system, you want about 2-3” of substrate covering the gravel stand.  If you are not doing a UGF or RUGF filtration system, use less than .5”.

4.    Fill the tank with about 1-2” of water.  Verify that your tank is firmly in place and that it is level.  An unleveled tank can lead to torsion cracks.  The last thing you want is a soaked living room!  If your tank is not level, you can try slipping paper under the loose corners.

5.    Fill the tank with water until the water level is 1” below the top.  If you trust the water that comes out of your garden hose, it’s perfectly acceptable to use it at this time.  (Don’t know if you can trust it?  Take a big swig of it).  If your water isn’t clean enough, you may want to go to the store and buy distilled or filtered water in gallons, or use water from a faucet inside your house.

6.    Check to make sure that the substrate was not disturbed while you were filling the tank.  Level out and disturbed substrate.

7.    Affix your heater(s) and/or chiller(s) to the inside of your tank.  Over the next several hours slowly adjust the temperature in your tank to 78°F.  Overworking heaters can damage them.  (In the meantime, proceed to step 8).

8.    If you are using any other filtration devices, connect them now.

9.    Activate your filtration system(s) buy turning them on.  Verify proper operation.

10. Slowly add your instant seawater mix until the specific gravity reaches 1.022.  Some seawater mixes take longer to dissolve than others, so keep this in mind when you’re reading specific gravity—the changes don’t take place instantly.

11. Place the lid or cover on your tank and affix your lighting system.  Put your lights on a timer so that they are on for 14 hours during the day.

 

After your temperature and specific gravity are stable it’s safe to add fish.

 

2.3 Adding Fish

 

Acclimating fish to your tank can be tricky.  Timing plays a key role in the fish’s survival during this stressful time period.

 

The first step, when you get the fish home from the pet store, is to place the bag the fish came in inside your tank, propping it up so that no water is exchanged between the fish’s bag and your tank.  The pet store’s water is most likely contaminated with disease, and you don’t want to harm the fish you already have.

 

After about 15 minutes the fish should be acclimated to your tank’s temperature.  Now you want to slowly adjust the fish to your water.  You do this by taking a cup of water from your tank and adding it to the fish’s bag, and then taking a cup of water from the fish’s bag and disposing of it.  Do not add the fish’s water back to your tank!  Do this about every 10-15 minutes for an hour.

 

Once the fish is acclimated to your water you can catch it with a fish net (while it’s still in the bag), and then release it into your tank.  Dispose of the pet store’s water; do not add it to your tank!

 

If you have kept marine fish for some time, you may want to perform what’s called a “freshwater dip” on your new fish before you add them to the tank.  Freshwater dipping causes protozoan that may be clinging to the side of the fish to break lose, so that they are not added to your tank.

 

To do a freshwater dip, prepare some water from your tap that has been treated with an anti-chlorine agent, and is the same temperature as your tank.  Then, using a pH raising product, bring the pH of the freshwater up to the same as your tank.  Now, when the fish is done acclimating to your tank water, and right before you add it to the tank, catch the fish from the bag and place it in the freshwater for no more than 30 seconds.  If the fish shows any signs of stress transfer it immediately to your tank.

Glossary

 

Actinic – If a fluorescent bulb is “actinic” it implies that the bulb radiates ultraviolet light required for certain chemical reactions.

 

Corrode – To weaken or wear away at something slowly.  Corrosion can occur with a metal if it comes in contact with a corrosive substance such as seawater.

 

Ion – A charged sub-atomic particle, such as a free electron.

 

Gas exchange – A general term referring to the transfer of gases between two systems.  In the marine aquarium the two systems are the water in the tank and the air immediately above it.

 

ppm – Stands for “parts per million”.  ppm is derived by taking a liter of solution and measuring the particle concentration of the solute.

 

Solute – A dissolved substance, usually in water.  In seawater, NaCl is said to be a solute.

 

Sump – A reservoir acting as a receptacle for water.  A wet-dry filter uses a sump underneath it to hold water before it is pumped back into the tank.

 

Torsion – Twisting or wrenching of a particular object.

References

 

  1. Axelrod, Herbert R. Saltwater Aquarium Fishes. Neptune City, NJ: T.F.H. Publications, Inc., 1987.
  2. Kay, Gordon. The Tropical Marine Fish Survival Manual. New York: Barron’s, 1995.
  3. Spotte, Stephan. Captive Seawater Fishes, Science and Technology. New York: John Wiley and Sons, Inc., 1992.
  4. Thresher, Ronald. Reef Fish: Behavior and Ecology on the Reef and in the Aquarium. St. Petersburg, FL: Palmetto Publishing, 1980.
  5. Unknown Author(s). The Saltwater Aquarium Guide. http://www.marineaquarium.org.  (March 2000).

 

 


† In your author’s opinion!

† This “stickiness” is due to H2O being a “polar” molecule.  The Hydrogen atoms bond with the Oxygen atom at a 105º angle, leaving the Oxygen side of the molecule negatively charged and the Hydrogen side positively charged.