Aquarium Maintenance


Thank you for taking the time to read this material. We trust that it will serve to answer most of your questions as they arise. Hopefully, it has not left you with reservations that successfully maintaining an aquarium is an arduous task. Nothing could be further from the truth. Primarily, it's a matter of common sense. Fish, and other aquatic denizens, cannot survive in polluted water.

Take a few moments each day (feeding provides an excellent opportunity) to observe that everything in the aquarium is functioning properly, evaluate the overall condition and appearance of the fish and other inhabitants, remove any uneaten food material or other debris on the substrate and/or ornamentation and remove any water spotting on the glass or aquarium trim. If the fish appear to be behaving abnormally, make the appropriate tests to insure proper water quality and look closely to see if there are any visible signs of disease.

Twice a month devote the small amount of time required to perform partial water changes and gravel vacuuming, service the filters as required, scrape algae from the glass and check water quality. The result will be a trouble free, long term successful aquatic experience. ENJOY!

Gravel Vacuuming and Partial Water Changes

  • Regular, periodic partial water changes are mandatory to maintain proper water chemistry. A 25% water change every two weeks is recommended. Smaller volume, more frequent water changes are even more beneficial.
  • Fish respiration, fish digestion and the decay of uneaten food generate three nitrogenous compounds; ammonia, nitrite and nitrate. The first two, ammonia and nitrite, are toxic to fish and extended exposure to them or introduction of fish to these compounds from non-contaminated water will result in disease and/or death. Nitrate is considered to be harmless to most fresh water species. At low levels it is stressful to saltwater fish; at high levels it can be toxic.
  • In an established (cycled) WELL MAINTAINED aquarium there are nitrifying bacteria present which will convert ammonia and nitrite into a relatively non toxic compound (nitrate). Nitrates can only be removed from the aquarium by performing partial water changes.
  • When performing partial water changes, the gravel should be simultaneously vacuumed to remove trapped debris and uneaten food to insure an adequate oxygen supply to the nitrifying bacteria and to remove undesirable nutrients.
    • Unplug heaters, power filters, powerheads and air pumps.
    • Remove ornamentation other than live plants.
    • "Walk" the gravel cleaner across the entire bottom of the aquarium, agitating the substrate in the gravel cleaning tube until the water being extracted is free of debris. If water is being removed too quickly to remove all the debris, pinch the gravel cleaner hose to restrict the water flow.
    • In freshwater aquariums add dechlorinator and aquarium salt per manufacturer’s instructions TO THE AQUARIUM.
    • Refill the aquarium with water of the SAME temperature as that of the aquarium water.
    • In saltwater aquariums, the replacement water must be dechlorinated, premixed and prebuffered before being added to the aquarium. ALWAYS dechlorinate the water prior to the addition of sea salt. Some marine salts now include a dechlorinator in their ingredients. However, this dechlorina- tor is not uniformly distributed throughout and should not be relied upon as the sole source of dechlorination. Premixed saltwater should be aerated or otherwise agitated for 24 hours before being introduced into the aquarium to insure that the specific gravity and pH are correct.
    • Restart filters, powerheads and air pumps.
    • WAIT fifteen minutes BEFORE plugging the heaters back in.
  • There are specific circumstances that will somewhat alter the above procedure. These include:
    • If the pH is extremely low, several small volume water changes (approximately 15%) must be done twenty-four hours apart. A single, large volume water change will put the fish into pH shock, probably resulting in multiple fish death. This is particularly crucial if ammonia is also present. Raising the pH will chemically alter the ammonia increasing its toxicity.
    • DO NOT do gravel vacuum/partial water changes while the nitrification cycle is occurring unless you are experiencing multiple fish death. Water changes will lengthen the time frame for this required cycle to complete itself.
    • If your aquarium is not equipped with an undergravel filter, gravel vacuuming and filter maintenance should not be performed at the same time. The consequent loss of a large percentage of nitrifying bacteria can cause temporary ammonia and nitrite related stress to the fish. These two functions should be performed at one week intervals.
    • Continually "topping off" aquariums to replace evaporated water increases toxicity concentration as toxins do not evaporate. Such water replacements do not constitute a water change.

Power Filters, Powerheads and Water Pumps

  • Periodically remove the impeller. Clean the impeller and the impeller seating area to remove debris and slime coating which retard the electromagnetic field.
  • Keep the intake strainer and/or prefilter clear of debris.
  • NEVER restrict the intake flow of water. Any adjustments to flow rate must be made to the exhaust.
  • Other specific maintenance per manufacturer’s instructions.

Filter Media

  • Disposable filter cartridges should be replaced monthly. Filters re-circulate the same water over and over. Regardless of where particulates collect - whether it be the aquarium bottom or in the filter - they will be broken down to produce ammonia. Monthly replacement will remove the particulate from the aquarium and keep the flow rate from slowing down due to clogging.
  • Reusable and/or biological filter media should be washed in water taken from the aquarium. Chlorine in tap water is lethal to nitrifying bacteria.
  • Micron cartridges should be cleaned by soaking in a solution of unscented household bleach and water (one part bleach to five parts water) for several hours. Rinse thoroughly under pressure. As an added precaution, they can be soaked in a solution of water and dechlorinator prior to being reused.
  • Chemical filter media; carbon, ammo carb and ammonia chips should be replaced each month. These media remove molecules of organic compounds from the water UNTIL the surface area becomes saturated. Once saturated, these media are no longer effective and may, in fact, begin releasing compounds back into the water.
  • Several manufacturers now offer rechargeable chemical media as an alternative to carbon. These should be used and recharged in accordance with manufacturer’s instructions.
    IMPORTANT: If, for any reason, the power filter has been shut off for two hours or less, biological, chemical and mechanical filter media should be thoroughly rinsed before restarting the filter. To preserve existing nitrifying bacteria, rinse the biological filter media with water taken from the aquarium. If the power filter has been off for more than two hours, the mechanical and chemical filter media MUST be discarded and the biological media thoroughly rinsed. Toxic, anaerobic bacteria will be present.

Air Pumps and Air Stones

  • Diaphragms and flapper valves have to be replaced periodically as symptomized by reduced output and/or noisy operation.
  • If your air pump is equipped with a fibrous filter, replacing this filter regularly will greatly prolong pump life.
  • The purchase of a supplementary battery air pump is highly recommended to prevent the loss of oxygenation during power outages.
  • Air stones eventually become clogged as evidenced by reduced bubbling and should be replaced to prevent the loss of nitrifying bacteria and damage to the air pump. Soak new air stones in water for several hours before installing them in the aquarium.

Aquarium Glass

  • Clean the exterior glass with glass cleaner and paper towels. Spray the glass cleaner onto the paper towel rather than onto the glass itself to prevent over spray into the aquarium. Glass cleaners contain chemicals that are toxic to fish.
  • Clean the interior glass with an algae scrubber pad. Ideally, do this just prior to changing the filter media or doing a partial water change so that dislodged algae will be removed from the aquarium.
  • Glass canopies should be cleaned regularly to provide maximum penetration of light.

Fluorescent Aquarium Lighting

  • Fluorescent tubes and starters should be replaced every twelve months to provide maximum visual quality and plant growth.

Artificial Plants, Rocks and Other Ornamentation

  • Surface algae and dirt can be removed by soaking in a solution of unscented household bleach and water (5% bleach). Rinse thoroughly before returning to the aquarium. Porous rock should be soaked in a solution of water and dechlorinator prior to being put back into the aquarium. DO NOT soak driftwood in bleach. The surface can be cleaned by scrubbing with a soft bristle brush.
  • Some medications consist of permanent dye base solutions. Remove porous surface decorations while medicating.

Live Plants:
(Courtesy, Stan Makowski; Jermack Cultivated Plants)

  • "TRIM BUNCH PLANTS BEFORE PLANTING. Remove the weight, trim as many leaves from the stem as is practical, then replace the weight in a spiral fashion, but not too tightly. Some plants will survive without this simple procedure, but more often the leaves under the weight rot over the first week or two, and this causes the stem to deteriorate at the base and the rest of the plant to surface. When planting rooted plants, it is critical that they not be placed too deeply in the gravel. The top of the root structure should be visible. Once established, live plants should be pruned periodically.
  • MAINTAIN ADEQUATE LIGHTING. Recent research indicates that the intensity of the light is even more critical than the duration. A single full spectrum bulb may be adequate for a ten gallon (or other 12 inch aquarium) but taller tanks need a higher degree of luminance. Some modern reflectors or hoods have the capacity to hold two bulbs. If this is the choice you make, we strongly suggest that two entirely different types of bulbs be used: a full spectrum bulb in front so that your fish show to their best advantage and a bulb more advantageous to plant growth in the rear.
  • REMEMBER TO USE FERTILIZER. Most liquid fertilizers, in addition to replacing needed trace elements and nutrients, actually aid in changing mulm into substances that are more easily absorbed by the plant’s roots. A good quality liquid fertilizer may be adequate for a beginner’s aquarium or even one of small dimensions. However, those wanting optimum results would be wise to also purchase one of the many products that apply fertilizer directly to the gravel.
    • If phosphate is present (Nashville tap water: 1 ppm), the available iron will chemically combine with the phosphate forming a compound which is insoluble by the plants. An iron deficiency condition known as iron chlorosis may result. The plants turn yellow and the leaves and stems both become very brittle. Fertilizers containing iron supplements will correct this condition.
  • FILTRATION. Avoid an undergravel filter if at all possible. For reasons not yet completely understood, undergravel filters appear to inhibit aquarium plants from absorbing certain vital nutrients. As a result, plants may become stunted and pale yellow in color, indicating that photosynthesis is somehow disrupted. If you already have an undergravel filter and don’t want to remove it, consider leaning heavily on potted plants.

Also to be avoided in heavily planted aquariums are devices which would enrich the water with oxygen and/or cause carbon dioxide to escape. These include power filters whose return flow causes heavy surface turbulence and airstones. Trickle filters are also not recommended as the filtered water contains almost no carbon dioxide.


  •  DO NOT OVERFEED. Two or three times daily feed your fish ONLY what they will actively consume in 4 - 5 minutes time. To insure adequate nutrition, provide a varied diet. Uneaten food should be removed from the aquarium. Contrary to many manufacturer’s claims, overfeeding will result in cloudy water, excessive algae growth and deteriorating water quality. While your aquarium is going through nitrification, we suggest you feed your fish only once a day to limit the amount of waste introduced into your new aquarium.

Water Quality

  • "Tap water is supplied for one purpose - human consumption. It is carefully screened, cleaned, treated with prophylactic chemicals and pumped into our homes for our use. It does not, however, carry a guarantee that it is suitable for fishkeeping!" (Courtesy, The Encyclopedia of Tropical Aquarium Fish; Dick Mills and Dr. Gwynne Vevers; Tetra Press; page 24).
  • It is imperative that the hobbyist have an understanding of the properties of water, the importance of maintaining water quality and the necessity of using test kits to monitor water quality.
  • The following water qualities can, and should, be tested with the appropriate aquarium test kit on a regular, continuing basis or whenever something appears to be amiss:
    • pH:
      pH of water is a measure of acidity or alkalinity. The pH ranges from 0 to 14, with 7 as the neutral point. Above pH 7 water is alkaline; below 7 it is acidic. Nashville tap water will usually measure between 7.0 and 7.3. This is ACCEPTABLE for MOST freshwater species you will encounter. African cichlid and marine aquaria should be maintained at a level of 8.2 to 8.4 ALWAYS test tap water pH prior to making freshwater aquarium water changes, and adjust as required.
    • Ammonia:
      Ammonia is the most toxic product formed in water. Sources of ammonia in aquarium water are fish respiration and digestion and decaying foods. Freshwater fish begin to be stressed at levels of .50 ppm (parts per million). Marine aquaria levels should be less than .05 ppm; reef tanks at 0 ppm.
    • Nitrite:
      Nitrite is the toxic intermediary product created in the process of breaking down organic waste products. It occurs between ammonia and nitrate in the breakdown sequence. Levels above 1.0 ppm are to be avoided in fresh water aquaria. Saltwater levels should be maintained at less than .05 ppm; with levels above .10 ppm being critical. Nitrite levels in reef aquaria should be 0 ppm.
    • Nitrate:
      Nitrate is a mildly poisonous end product of the breakdown of nitrogenous waste products in the aquarium. While thought to be harmless to MOST fresh water species, fresh water aquarium levels should not exceed 300 ppm. Less than 50 ppm is the desired level for saltwater aquaria. Reef tanks should be maintained at less than 5 ppm. High nitrate levels in both fresh water and saltwater aquariums will promote excessive algae growth.
    • Chlorine:
      Chlorine is a chemical additive used to destroy bacteria. It is lethal to fish at .2 - .3 ppm.
    • Alkalinity:
      Alkalinity is a numeric measure of the resistance of water to a change in pH as acid is added. The higher the number, the better.
    • Hardness:
      Hardness is a measure of dissolved calcium and magnesium salts in water. Nashville tap water usually ranges from soft to medium hard., This is ACCEPTABLE for MOST freshwater fish and plant species. If the water is too hard for your specific application (such as breeding certain species), simply mix it with deionized water until the required hardness is obtained. Most hobbyists will not have need to measure this particular water quality.
    • Specific Gravity:
      The specific gravity (or density) is the ratio of the amount of total dissolved salts in water when com- pared to pure water. Pure water has a specific gravity of 1.000. As more salts are added to the water, the specific gravity increases. Marine aquariums should have a STABLE specific gravity of 1.022 to 1.027 with a median value of 1.024 being best.
    • Calcium:
      Calcium carbonate is the building block of coral skeletons, clam shells and calcareous algae. Corals, soft corals, clams, snails, scallops, shrimps, crabs, starfish, sea urchins and some algae extract calcium from the water continuously. Reef aquarium levels should be at least 400 ppm.
    • Phosphates:
      Phosphate is a salt, commonly found in tap water, which serves as an algae nutrient. Maximum phosphate levels are 2 - 3 ppm with less than .05 ppm being ideal. Reef tanks should be maintained at less than .05 ppm. Nashville tap water has a phosphate level of 1 ppm.


Adjustment and/or corrections to existing water chemistry MUST be made gradually.

Stability is as important as water quality.