[leebca]

WATER QUALITY

Often spoken about, but what is it?

Most often heard from marine aquarists: “My water quality is good; Ammonia = 0; Nitrites = 0; Nitrates are less than 10; phosphates below 0.01; pH, calcium, alkalinity, and magnesium in range; Temperature in range; and Specific Gravity in range.” Is the water quality ‘good’ though? Those test results would indicate a water problem but those test results do not indicate the water quality is good.

There is much more to water quality than just ammonia, nitrites, nitrates, pH, calcium, alkalinity, magnesium, temperature, and salinity. These are the things that can be measured by available test kits, equipment, and devices. They are important but far from all inclusive. These conditions are just a tip of the iceberg of what is in the captive marine aquarium water system.

The reader will find many of my posts relating problems with fish(es) to water quality. It doesn’t mean the poster has high ammonia, nitrites, phosphates, etc. although one or more of these can be the case. It means that something is wrong with the water that goes beyond the test kits, or is indicative of chemistries that are not balanced. What are those other things and how do you know the quality is ‘off?’


ORGANICS

This component of the marine aquarium water is the most common untested ‘pollutant.’ It comes from invertebrates, corals, fishes, pods, benthic creatures, microbes, live rock (cured and uncured), and all aquarium marine life. It is added to the aquarium by the aquarist through feeding and other additives. Maybe a friend decided a little food is good so more is better. Maybe the aquarium keeper has not been properly trained on how to feed the life forms. This is usually classified into the general category of dissolved organics.

If these organics are not kept low in concentration, they encourage microbial growths (e.g., diatoms, bacteria, micro algae, etc.) in large numbers, called a ‘bloom,’ that interferes with the health and/or metabolism of some marine life forms. Signals of high organics include: a yellow tint to the water, a surface (oily) sheen, bubbles linger rather than 'pop' as soon as they are formed, cloudy water (with bacteria), swings in pH, fish breathing faster than normal, and strange behavior or health of fishes. In particular high organics and thus high bacterial count can cause the fish to contract a cloudy eye now and then or suffer bacterial infections, or virus infections (like Lymphocystis). I have witnessed on more than one occasion that a tank of fish, in high levels of dissolved organics, act irritated. They may actually scratch or flash more than normal. So when an aquarist complains their fish has a cloudy eye or the cloudy eye comes and goes, high organics is something to investigate as well as other causes of bacteria population blooms.

Most captive marine fishes can defend themselves against a bacterial infection, but not when the numbers of bacteria are huge compared to their normal (ocean, sea, reef) environment. So keeping organics to a minimum to prevent bacterial blooms is essential to good water quality and the health of the captive marine life forms. Large populations of bacteria consume oxygen and produce carbon dioxide causing swings in the pH. This is about the only routinely tested feature that may lead one to consider the possibility of there being a higher-than-desired concentration of organics.

Probably the best known organic water quality controls are the use of activated carbon, the use of a protein skimmer, and water changes. To some extent, a refugium can be a means of reducing dissolved organics when the life forms are chosen that utilize organics. However, a refugium can also be a source of organics!

The protein skimmer does not remove all proteins from salt water. There are certain kinds of organics that are not efficiently removed by the protein skimmer process. These include several of the fatty acid and lipid organics. So besides keeping the protein skimmer clean and working at its maximum ability (see below), the aquarist wants to use some organic adsorbent/absorbent material, such as activated carbon, to remove those other organics that are not efficiently removed by the skimmer. Should everyone use a skimmer and activated carbon? No. Keep reading.

First, the skimmer. The optimal target is to have a skimmer that will process about 1.5 times the volume of water in the entire marine system, every hour. As an example, for the average bio-load system with a total volume of 115 gallons, the skimmer should process no less than 160 gallons per hour. There is no ‘standard’ skimmer rating system, unfortunately. Most manufacturers will stretch their product’s skimming ability, so it’s hard to give advice to the aquarist on what to buy. If the processing gallons per hour is not specified by the manufacturer, then in general, I recommend the aquarist purchase a skimmer rated between 2 and 3 times the volume in the system. So if the system contains 115 gallons as in the above example, the skimmer should be rated for about 250 gallons. After its choice, it must be operated to its full efficiency. Don’t reduce the recommended pump flow; keep the air intake clean and open; keep the bubble chamber walls clean and the collection cup clean. The skimmer only works best when it is clean. How often to clean? No less than every other day. Daily cleaning is recommended by me for a high bio-load system (see below).

Second, the organic adsorbents/absorbents. If the aquarists wishes to use activated carbon in addition to using a skimmer, I recommend to use about 1 pound dry carbon for every 100 gallons of system water. In addition, the choice of carbon should be one that doesn’t release phosphates or other materials into the water. So, in the above example, the aquarist will want to use a bit more than 1 pound of dry activated carbon. I further advise that it be used constantly for only about 10 to 14 days (14 in low bio load system; 10 in high bio load systems). Then remove it and discard it. Leave the system without carbon for another 10 to 14 days, then put fresh carbon back in. Continue this cycle. The reason for this is that old carbon stops adsorbing significant quantities of organics and just continues to remove trace elements. With the use of a skimmer, the carbon is capturing organics for up to 2 weeks and then slows down to the point where about the only things being removed from the water are trace elements. Also, the carbon doesn't have to be constantly there to provide the needed export. The on/off use of the carbon is quite satisfactory, in general, for a normal bio loaded system that is also using a skimmer. There are now a few choices of organic absorbing material. The aquarist wants to know that is absorbs fatty acids and lipids for sure, and that the material doesn’t release anything into the water, including what it has absorbed.

Third, water changes. Water changes can correct a world of wrongs. Diligently performing water changes is an important means to export excess organics that the other means leave behind.

Skimmer and adsorbent/absorbent always needed? No. A system with a low bio load can probably get away with either a skimmer or carbon. A real low bio load system (one with no ammonia-nitrogen waste producers – like in a reef-only system) may not need either. [NOTE: A low bio load doesn't always take into account protein concentration. For instance many marine life forms release organics into the water as a means to defend their territory or inhibit competitors. They may not create typical ammonia-nitrogen wastes which is what 'bio load' is usually connected with.] Also, if the aquarist is doing very large and frequent water changes, this is a fine alternative fast export of organics and a skimmer and carbon may not be needed at all. A medium bio-load and nitrogen waste producing system that is being fed by the aquarist should have at least one or the other and preferably both. The heavy bio-load system, like in a FOWLR system, should use both organic controls.


POISONS

This is the second largest source of pollutants that prevent the water quality from being really ‘good.’ This includes oxidizing metal (rusting) equipment and connections, glue, uncured or improperly cured resins, decorations, rocks (trapped metals, etc.), unusual substrates, condensation from hood and lighting equipment, foods (some contain pollutants), fumes and mists (paints, chemical household cleaners, cooking, etc.), and intentionally added things (that don't belong in the water). In this last group are children that think “Nemo” might like some Cheerios or candy. Sometimes it’s just an adult who thinks that if a little is good, then a lot is better. Unfortunately, I've known two cases of intentional sabotage.

The system and its inhabitants react to these in many different ways. Sudden death of sensitive fishes. One death or one fish being affected doesn’t eliminate the poison pollutant possibility. When only one fish is affected, it reduces the chances of it being a water pollutant, but doesn’t eliminate it. Different kinds of fishes have different pollutant tolerances, and even within a species, different fish have their own personal threshold tolerance to pollutants.

Finding the source and type of pollutant requires a lot of detective work on the part of the aquarist. Maybe the aquarist left the system care to a friend or neighbor while on vacation or on business travel. The keeper can be interrogated, but unlikely to admit to any wrong doing.

Determining there even is a pollutant in the water can be challenging. How to find something that cannot be tested? Water clarity; microbe activity; live stock reactions (from signs of stress, irritations, diseases, to death); and coloration about the most often encountered signs. Fluctuating and unexpected pH readings can indicate a pollutant that affects the buffering ability of the water or directly affects the pH of the water. Watching this water feature closely is important and the aquarist becomes weary of being diligent after many moons have passed being in this hobby. Sometimes a pollutant shows up from a source the aquarist previously determined was okay. The most common of these is a shift in source water quality. A DI system can expire and fail to provide the pure water previously expected. An RO system can fail from damage to the membrane. Checking the water source is important, especially before taking the recommended (see below) corrective action.

The best thing to do when there is a chance of a poisoning, is perform a very large water change. Over 60% of the entire system water needs replacing with newly prepared salt water that is not polluted. Special attention needs to be given that the water change is done properly. See this: how do I do a water change?



MATURING AQUARIUM

Many new marine aquarists don’t understand that a new aquarium is going through many changes (chemical and biological) that are not measured by test kits. Sometimes the problem with a particular marine life form is that the aquarium hasn’t settled down. The water quality progresses through unseen changes until the aquarium matures when these changes are less frequent and less pronounced. I won’t cover the mature aquarium in this post (again), but refer the reader to these other posts:
The Secret Cycle
The Mature Aquarium

It’s worth pointing out here, though, that signs of an immature aquarium include microbe activities, like ‘brown algae,’ slimes, red algae, etc. Fish, corals, and sessile invertebrates should not be added to a system showing any of these signs of immaturity.

The fix is simple. Give it time and patience. Sort out the source of excess nitrates, silicates, and/or phosphates, and give the system time to settle.



BALANCE

Just because the marine system is FOWLR doesn't mean the aquarist can ignore the need for chemical balance. By this I mean the ratio between calcium, alkalinity, and magnesium. Snails and the coralline algae are, minimally, dependent upon the proper balance of these components.

To over simplify the concept -- It is the goal to keep enough carbonates, calcium and magnesium dissolved in the water at the right pH, so that dependent marine life can find it easy to precipitate (take out of solution) what they need to make their calcareous shell, skeleton, etc. On the other hand, the aquarist doesn't want the precipitation of carbonates (the infamous milky cloud! ) in the water. This requires a balance.

Although the aquarist is told to keep pH, alkalinity, and calcium within a certain range, it is AS IMPORTANT to keep them in balance, within that range. Following is a suggested balanced relationship between these three:

Calcium - - - Alkalinity - - - - Magnesium
- (ppm) - - - dKH - meq/l - - - (ppm)
410 - - - - - - 7.0 - - 2.50 - - - - 1100
414 - - - - - - 7.5 - - 2.67 - - - - 1100
417 - - - - - - 8.0 - - 2.35 - - - - 1100
421 - - - - - - 8.5 - - 3.03 - - - - 1150
425 - - - - - - 9.0 - - 3.21 - - - - 1150
428 - - - - - - 9.5 - - 3.39 - - - - 1175
432 - - - - - -10.0 - -3.57 - - - - 1175
435 - - - - - -10.5 - -3.75 - - - - 1200
439 - - - - - -11.0 - -3.92 - - - - 1200

From the above the aquarist should be able to deduce that if the calcium concentration isn't between 410 and 440, then the marine system is not in balance. When the calcium is between these numbers, then there needs to be the corresponding alkalinity. Aquarists running calcium in the 300's ppm and a (for example) 'recommended' alkalinity (between 7 and 9 dKH) have water that is out of balance and thus, low water quality.

An imbalanced water chemistry can cause the pH to be out of control. The pH, alkalinity, calcium, and magnesium are all connected to one another. (See: A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH by Randy Holmes-Farley - Reefkeeping.com). As the aquarist chooses the higher alkalinity concentrations from the above table, the pH generally goes down to accommodate keeping the would-be precipitate of carbonates in its dissolved state. An incorrect or fluctuating pH (even as little as 0.05 pH units for some fishes) causes a great deal of stress to the fishes -- more than a shift in salinity.

Further, an imbalanced water quality can cause hardening or clumping of some substrates, precipitation of carbonates in plumbing and pumps (thereby restricting flow), the slow grow or death of calcareous marine life, and the wrong kinds of algae to bloom or take over.

Simply brings things back under control. Make chemical adjustments to bring things back into order. Also, check the salt mix that is used to be sure it is balanced. If it isn't, then you'll routinely need to adjust the salt water before performing a proper water change (see: how do I do a water change?).

Take note though. . .Precipitated carbonates will not redissolve even when chemical balance is restored. Plumbing, equipment, etc. need to be taken apart and manually cleaned (with a diluted vinegar solution) to remove calcareous precipitates. Clumped or hardened substrates will need to be removed in order to prevent oxygen and water from entering the substrate and avoid anaerobic bacteria producing hydrogen sulfide.


CUSTOM QUALITY

This last consideration has to with the preference of the life form. Maybe the marine life is too close to the light or too far away. Maybe the fish prefers water of a higher pH or higher salinity. There are some water quality considerations that are related to the marine organism being kept captive. Most aquarists are familiar with the requirement for very low nitrates when certain corals and invertebrates are kept in the display aquarium. Similar special needs are sometimes required by other marine life forms. This is usually something we don’t worry about, but if the aquarist is properly prepared before the acquisition of the life, then it may be apparent what conditions it comes from and what conditions it requires. If those conditions aren’t provided, the life becomes ill or dies.


WHAT IS THE WATER QUALITY OF YOUR SYSTEM?

It’s a bigger picture answer. The answer goes beyond test kit measurements so before answering the question with ‘water quality is perfect because all the parameters are perfect’ remember the test kits and devices only look at the tip of the iceberg!


Anyone interested in other informative posts and links, please click on: Table/Contents - Link List for a list.

[kronos5]

Very Informative - Thanks