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Water Conditioners

Chemicals to Alter Your Aquarium Water

(The First Tank Guide)

Aquarium water conditioners are any chemicals added to the aquarium water - either before the water is added to the fish tank or to the water in the fish tank itself - in order to "condition" or alter the water in some way. Conditioning the water can vary considerably from merely removing chlorine from tap water to altering the pH of the water.

Generally, water conditioners fall into four categories:

  1. The water conditioner you need
  2. Chemicals that may have benefits for some aquarium owners in some cases
  3. Chemicals that are necessary for specific, usually fairly advanced, fish or aquarium care
  4. Chemical additives you want to avoid

The Aquarium Water Conditioner You Need

There is only one water conditioner you need, and that's a dechlorinator (and you may not even need that one). If you're on a municipal water supply, or you are on a well system where your water is stored and treated with chlorine or chloramine to keep the water safe and germ-free while it is being stored, you need a dechlorinator.

Get a good one, they're cheap and easy to come by - all pet stores will carry several dechlorinators, and most pet stores will have a good dechlorinator that doesn't try to do a lot of other things, and is dosed in some variation of drops per gallon.

A dechlorinator is the only aquarium water conditioner you actually need.

Aquarium Water Conditioners You May Want

There are a variety of other water conditioners you may want to get at some point. These vary from plant foods to medications, and even include aquarium salt. Yes, aquarium salt is a water conditioner, as it changes the condition of the water!

These aren't necessary for your beginner aquarium, and will often actually make things more complicated, so unless you know what you are doing, why you are adding a particular water conditioner, what the water conditioner does - or is supposed to do, how to know if the water conditioner is doing what it is supposed to do, and the possible negative side effects of using this particular water conditioner, you probably don't want to be adding a water conditioner to your new fish tank.

Aquarium Water Conditioners for Special, Advanced Aquariums

As you become more experienced with your fish and fish tank you may decide you want a more challenging experience with your aquarium. Toward this end, you may decide to look into some more exotic types of fish or a more exacting type of aquarium setup. Sometimes these special cases will mandate some additional type of aquarium water conditioner.

The most common of these is probably aquarium salt. If you choose to set up a brackish water or marine aquarium, you will need to add salt to the water. It is important that you use the right kind of salt and that you use the right amount to maintain the specific gravity necessary for the fish you are keeping.

There are also various specific "salts" or extracts designed to provide water chemistry closer to specific regions of the world. Some particularly sensitive and delicate freshwater fish do much better the closer you mimic their native water across a variety of parameters, including the specific levels of particular trace elements and other impurities in the water. However, this is not necessary for most fish.

Another common group of water conditioners is plant food. If you decide to take on the extra challenge of raising live plants in your fish tank, those plants will need care as well. There are many aquarium plant foods on the market, and which one or ones you need will depend a lot on the kind of plants you are trying to grow, the amount and type of aquarium lighting you have on the tank, the type of filter you are using, and what your source water chemistry is like to begin with.

These special additives and water conditioners are not necessary for most aquariums, and can even lead to problems, not the least of which is water clarity.

Chemicals You Want to Avoid

For the most part, any aquarium water conditioner other than a dechlorinator is something you want to avoid. There are a lot of "snake oils" out there being marketed to take money out of the pockets of unsuspecting new aquarium owners - and sometimes even very experienced aquarium owners. Remember, these generally aren't necessary, and can often have unwanted, even dangerous side effects.

Particular aquarium water conditioners you want to avoid are bacteria boosters (sometimes now sold as biological filter starters or biological filter boosters), ammonia removers, water clarifiers, and pH adjusters.




"Thanks for the info. I am just getting started and was hoping to find some good, easy to use info."
February 21, 2002
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"Just wanted to let you know that your tips worked. We've got a healthy tank now with several tetras that are doing just fine and all of our water quality measurements are within specs. Thanks so much for the pointers."
June 17, 2009
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