While most hobbyists are blessed with reasonably good tap water to use to fill their aquariums, there are some water conditioners that will be required to make the water safe for the fish or needed to adjust the water to more closely match natural conditions. Unless the hobbyist has well water, the tap water will contain either chlorine or chloramines to kill bacteria in the water lines. While this is good for humans, either chemical can be deadly to fish and invertebrates in the aquarium. Chlorine is fairly simple to neutralize with any of the myriad of chlorine removers on the market. Chloramines are a bit more of a challenge, since it takes two steps to neutralize this chemical. The first step is to neutralize the chlorine, but this leaves the very toxic ammonia in the water. Chloramine neutralizers will have a second agent to chemically bind to the ammonia to make it safe. For this reason, it is important for the hobbyist to know what chemical agent is used in the local tap water. You can use tap water conditioners like AmQuel, Prime, Complete Water Conditioner or Ammo Lock II to eliminate chloramines in the water.

If the hobbyist wishes to adjust the pH of the water, understanding the General Hardness (GH) and Carbonate Hardness (KH) will be important. Marine aquariums are rather easy to keep at the proper pH range (8.0-8.4) with just the salt mix itself. If the fish load is too high, or not enough partial water changes are made, the pH in the aquarium may start to drop below 8.0. If this occurs, using marine supplement buffers like  Marine Buffer, Reef Buffer or Super Buffer dKH will help lock in the correct pH range. If the drop in the pH is caused by a lack of the proper alkalinity, this is usually associated with low calcium levels. The addition of calcium supplements or KH builders can usually stabilize the pH value. Freshwater aquariums with soft water can be easily maintained at the desired pH level with the use of water conditioner buffer products like Proper pH, Neutral Regulator, Acid Buffer/Alkaline Buffer, African Cichlid Buffer or other similar products. If the aquarium water is hard, changes in the pH will be difficult to impossible without the use of a reverse osmosis unit or DI unit.

The neutralization of ammonia was discussed in treating tap water, but it can also be found in the aquarium as a result of the natural metabolism of the fish. If the nitrifying bacteria of the biological filtration system are not capable of handling the ammonia wastes, ammonia will slowly build up to toxic levels in the aquarium. The use of the ammonia neutralizing agents can also be used at this time to protect the fish from the ammonia. Ammo-Carb and White Diamond are a few products made from Zeolite, a natural material that removes ammonia from water. These products can be placed in the filter system to continuously remove ammonia until they become exhausted and need replacement. This is most likely to occur in a newly set-up aquarium or in one where an antibiotic treatment has damaged the beneficial nitrifying bacteria. If you use water conditioners like AmQuel or Ammo Lock II to neutralize the ammonia, please be aware that most test kits will still register the presence of ammonia in the aquarium, but that the agents have chemically neutralized its toxicity.

While not toxic to the fish, phosphate in the aquarium can lead to excessive algae growth. The use of phosphate removal media like Phos Zorb, PhosGuard, PhosBan, Phosphate Sponge or Phosphate Filters can be used to remove any/all phosphate in the water. Phosphate is one of the waste products of food metabolism, so the level in the aquarium continuously increases. Phosphate is also found in tap water of some cities and can be removed with DI units or pre-treating the water with one of the above agents.

Usually, the best method to control nitrate levels in the water is to perform regular partial water changes. There are a few water treatments that will aid in removing nitrate, but these require proper set-up to work correctly. Many of these products do not actually remove nitrate themselves, but serve as a media/surface area for the bacteria that use nitrate as their oxygen source. To work properly, the denitrification media should be placed in a container where there is a very slow flow of the aquarium water through the media, the slower the better. In a marine aquarium, this media can possibly eliminate all of the nitrate, but the heavier fish load of a freshwater aquarium will usually require frequent partial water changes to control nitrate levels.

Activated carbon is perhaps the most common of the water conditioners, good at removing acidic wastes, organic wastes and discoloring agents (dyes from foods) found in aquariums. Other treatments include manmade resins designed to specifically remove wastes/chemicals in the water. BioChem Zorb, Purigen, Opti-Carb and Chemi-Pure are some of the most popular of the “general” resin water conditioners. CupriSorb is an example of a resin made to remove just one type of chemical (copper) from the water. The Poly Filter is an example of a fiber pad impregnated with chemical bonding agents to help purify the aquarium water. One advantage to some of the resin treatments is their ability to change color to let the hobbyist know when they are exhausted, and many can then be recharged and reused!

One of the newer classes of water treatments in the aquarium hobby is the introduction of probiotic treatments like Immune Plus or Marine Max. These products add thousands of beneficial microorganisms to the aquarium to more closely approximate the natural conditions. These microorganisms compete with harmful (pathogenic) microorganisms and also help trigger a better immune response in the fish, sort of like a vaccination for fish. These products have been used for years in the aquaculture industry, but have just recently become available to aquarium hobbyists. Along with the new high-efficiency biological filtration systems, these probiotic compounds can greatly enhance the quality of life for the fish.

Vitamin and trace element solutions can also be added to the aquarium water to help enhance the health of the fish and plants. Products like Vita Chem, Zoe Vitamins or Trace Elements are examples of some of the readily available conditioners for the aquarium. Most of the vitamin compounds can be added directly to the aquarium water or soaked into the food before it is fed to the fish. These vitamins can make up for any lost during the manufacture of the prepared foods. This can especially be important when conditioning fish before breeding them, and in raising the fry.

One last class of water conditioners to be discussed in this article is the clarifiers. These products help re
move floating debris, algae and sometimes bacteria found in the aquarium. Most work by causing the minute particles to clump/stick together until they become large enough to be trapped in the mechanical filter or else sink to the substrate. Examples of this type of product include Accu-Clear, Bright N’ Clear, Clear Water, and Tropical Clear. This last product also includes cultures of “sludge” eating bacteria to help control waste build up in the substrate. Aquarium Pharmaceuticals has an algaecide called AlgaeFix that can control the algae but does not bother the rest of the plants. This will certainly be a boon to the freshwater planted aquarium keeper!

This discussion has presented an overview of many of the different types of water conditioners available for the aquarium hobbyists. Most are designed to work in the aquarium, but a few can also be used to pre-treat the tap water to make it safe for the fish.

About The Author Pet Expert

comments (4)

  • Will a reverse osmosis system remove any chlorine or chloramines in the water? Our 55 gallon aquarium has a green color to it and it doesn’t seem to matter what we use in the water it is either cloudy or it has the green tint. We recently moved from Indiana to Tennessee and have had this problem since we moved down here. Any information would be greatly appreciated. Thank you!

  • Hi Richard, the green water is typically an algae bloom and that is what I suspect your issue is. This is not an uncommon thing in an aquarium, and there are a few ways of dealing with it effectively. The water you are adding to the tank has an excess of nutrients like phosphate in it, which is feeding the tiny floating algae in the aquarium. Adding a phosphate removing resin and replacing it often is one way to handle it, adding a UV sterilizer is another way to handle it, and using a new source of water is yet another way to handle it.

    So, your RO water question, the answer is yes it should help with your green water. RO water has no excess nutrients at all, so as you do water changes using RO water the nutrients will become more diluted and the algae will have less to feed on. Eventually you will starve the algae out, and your water will be clear. Be sure if you are using RO water that you actually use a product like Kent Marine's RO Right on the water before you add it to the aquarium.

  • I have a a 55 gallon cichlid tank. Been setup since February and fish in since mid march.
    I use a cascade 1000 canister filter. Three stages. 1-course foam,2-bio ceramics,3-the 10 ounce chemi-pure elite and polish pad, i also have a HOB FX4 filter with pad, purigen and matrix. Water is crystal clear and peramiters are perfect and still have alot of brownish red algae. Light on six to eight hours a day. No windows in area.
    My water company says we have high phosphates. This could be causing my problem. I do 50% water changes weekly. I think I'm feeding the algae and or diatoms before chemi-pure can neutralize.
    My question is. Should I buy a large container and pretreat water for a few days(6) with chemi-pure elite before putting in my tank?

  • Hi Donald –

    I asked our Live Deliveries Manager about your question, and here is what he had to say:

    Phosphate removers are only effective on a percentage of the phosphate if the phosphate levels are high. If phosphate is a major problem in the water going into an aquarium, it will cost a fortune in phosphate remover to get rid of the issue. It would be much more cost effective to use an RO water system on the water before it goes into the aquarium than it would be to try to use a chemical phosphate remover. But, the water will have to be adjusted back up with buffering agents before it will be suitable for a cichlid aquarium.

    If the “algae” is brownish red, and has a smooth appearance, then it is more likely there is a bacterial problem, and it isn’t algae at all. Another potential issue is lack of water flow in the lower levels of the aquarium, which would be an issue for either a bacterial problem or an algae problem. Point the return water flow on the Cascade down into the aquarium, if possible, instead of at the surface for a couple weeks and see if that helps. If that isn’t possible, consider adding a circulating powerhead down in the bottom of the aquarium (last resort, after you see if it is needed, once you identify whether the problem is really algae or bacteria… Don’t spend the money unless you have to).

    I hope that help!

comments (4)

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