There are test kits to test for ammonia, nitrites and nitrate levels.

The Ammonia Spike

If you already have tested your water with a test kit and you have an ammonia spike, here are some things you can do to help correct the problem right away:

• Do a 20% water change with dechlorinated water and continue to do this every day until the ammonia level drops.  The best ways to dechlorinate the water is to let it sit in a bucket a few days or to use a product like Seachem Prime, which also removes ammonia.  Be careful with other chlorine removers as these can also kill the valuable bacteria you are in need of.

• Test the water daily for ammonia levels.  If they remain high, you'll need to change more water.

• Keep good aeration in the tank to help develop bacteria.

• Avoid using medications, as these kill bacteria.

• Don't feed your fish at all if your ammonia readings are high, as this will cut down on the ammonia that the fish produce.

• Don't clean the gravel. You want to promote bacteria and gravel is an excellent location for this.

• Don't change your filter material.  Allow bacteria to develop there.

Maintaining Water Quality

There are a number of products that can help you establish and maintain water quality.  There are test kits and additives to adjust the pH and water hardness.  Seachem Prime is a very popular additive for de-chlorinating and it controls ammonia levels too.   Here's an excerpt from the Seachem website about Seachem Prime:  "Prime™ is the complete and concentrated conditioner for both fresh and salt water. Prime™ removes chlorine, chloramine and ammonia. Prime™ converts ammonia into a safe, non-toxic form that is readily removed by the tank’s biofilter. Prime™ may be used during tank cycling to alleviate ammonia/nitrite toxicity. Prime™ detoxifies nitrite and nitrate, allowing the biofilter to more efficiently remove them. It will also detoxify any heavy metals found in the tap water at typical concentration levels.Prime™ also promotes the production and regeneration of the natural slime coat. Prime™ is non-acidic and will not impact pH. Prime™ will not overactivate skimmers. Use at start-up and whenever adding or replacing water."

Why Zeo-lite is Not Recommended

The following information has been submitted by "LittleHippyGirl".   Zeo-lite is a chemical that is widely available in fish stores for its ability to suck up ammonia like a sponge. There are other brand names, but any ammonia-absorbing chemical would fall under this category. One would think, "why is this so bad?" Well, this is why it can be.

1) Once zeo-lite sucks up a certain amount of ammonia, it will not suck up anymore. There is no way you can tell how "full" the zeolite is until you suddenly have ammonia levels in the water and this could make your fish sick or weak. Granted, zeo-lite can be re-charged by soaking it in a container of salt water, its powers are not easilly monitered.

2) You can NEVER add salt to an aquarium with zeo-lite. Salt is useful in many ways, treating many types of diseases, helping wounds heal, and of course its mandatory in aquariums with brackish fish. Like said above, any salt in the water will cause the zeo-lite to let go of all the ammonia, immediately causing highly toxic and dangerous levels in your aquarium.

3) The most important downfall is that zeo-lite hinders the more natural nitrogen cycle. In a fully cycled aquarium, beneficial bacteria lives in the filter and changes ammonia into nitrite, and nitrite into nitrate. The first two are highly toxic, but nitrate is only toxic in higher numbers and this is reduced by vacuuming gravel and changing the water. In a fully cycled aquarium, the changes are so quick that the first two chemicals can not be detected in test results and your fish stay happy and healthy. However, zeo-lite will suck up the ammonia and starve the beneficial bacteria, crashing the nitrogen cycle. 

Having said all that, zeo-lite isn't entirely bad. No, it typically shouldn't be used in the home aquarium, but there are some situations that zeo-lite can benefit your fish. Sometimes aquariums under 5 gallons have trouble keeping a nitrogen cycle stable. Another acceptable case would be a temporary aquarium, such as a hospital or quarentine tank. Sometimes spare aquariums need to be unexpectedly and quickly set up, and you can not borrow media from another aquarium to jump start the cycle. For these exceptions, empty the filter of any sponges, media, cartridges etc and add zeo-lite. Do monitor the ammonia level carefully, and frequently re-charge the zeo-lite in salt water. Keeping a lot of fish in an aquarium with zeo-lite will make this maintenence more difficult but even more mandatory. Remember, you can not treat fish with salt in an aquarium with zeo-lite.