the only chemical I ever add to my water is prime to condition my water.
Other than that there no need to add any other chemicals unless your a chemist with extra time.
a good rule is never add anything you cant test for and if you can do with out do.

theres no need to change ph with most fish. besides if you lower your ph it will slowly go back up and will change when you add water to your tank. A fluxuating ph dose more harm that a less than ideal stable ph.

Maintaining Your Fish Tank

To keep your fish happy and healthy, maintaining your fish tank is crucial. It's easier than you think to keep a healthy tank that will let you enjoy your fish hobby for years. Just 30 minutes every other week will prevent most problems that can occur in your tank that can end up costing you a whole lot of time and money. Regular maintenance will also provide tank stability. It will amaze you how well your fish will withstand minor variances in the water as long as the tank is maintained and they are healthy.

Water Changes

If you've read anything about maintaining your fish tank, you've probably read about how important it is to change the water. With most aquariums, this should be done every two weeks. Before you start to panic and send your aquarium back to the store, you don't need to change all the water in the tank. Just changing 10-15% of the water is fine. A really good time to change the water is when you use one of those aquarium vacuums. This gets rid of leftover food and waste that settles into the gravel.

At the fish store, you'll find water testing kits. They are easy to use. Be sure and use them to check both the water in your tank and your tap water periodically to check the pH and what chemicals may be in the water. Tap water usually contains chlorine or chloramine. You can dissipate the chlorine easily by letting a bucket of water sit for 24 hours. It will work even better if you can aerate the water with an air stone. Chloramine, however is a combination of chlorine and ammonia. Even using a commercial water conditioner will get rid of the chlorine and leave the ammonia behind. If your aquarium is well-established, the good bacteria that are present will help break down ammonia, though it may take awhile. Watch your fish for signs that they are unhappy.

The water can also contain other contaminants like iron, heavy metals and phosphates. If you call your local water company, they can provide you with a report on the most current testing of water chemistry.

If you have access to well water, it is usually free of chlorine and chloramines, but it may be harder than tap water and may contain other elements from the surrounding soil.

The filtered water in your tank should be tested regularly when you do your regular maintenance routine. You want to check for silicate and silicid acid. These compounds can work their way through the membranes of the filter in a relatively short time.

Testing Your Water

Changes in your water are not visible, which is why testing is so important. Making testing a normal part of your maintenance routine will keep you on top of any chemical changes that may occur.

You can get a testing kit that will test for pH as well as nitrites, nitrates and carbonate hardness. Most fish do best in water that lies between 6.5 and 7.5 pH. This gives them a little leeway if it changes slightly either way. You want to keep the pH level as stable as possible. Carbonate hardness, or kH, tells you the stability of the pH. If it gets close to 4.5 dH (degree hardness) or 80 ppm, you need to take steps to raise it. Luckily, this is easy to do. What I do is add half a teaspoon of baking soda for every 25 gallons of water in your tank. This will raise the kH by approximately 1 dH, or 17.8 ppm.

You should not detect the presence of nitrites unless you are cycling your tank in preparation to adding your fish. If you do find some, check your ammonia levels too. Your nitrates (different from nitrites) should be kept to less than 10 ppm in freshwater tanks and 5 ppm in saltwater tanks. If you have a reef tank, you should aim for 0 ppm.

Aquarium Filtration

Keep your filter running properly at all times. Change your filter materials (cartridge, activated carbon or floss) at least every four weeks for optimal filtration. Particles become trapped in your filter and decompose. This gets cycled back into your tank if you don't change the filter material often enough. If you have many fish in your tank, you may want to change them more frequently. Clean your filter thoroughly once a month, but don't touch the bio-wheels if you have them. Use the water you remove from the tank during your water changes to clean the filter.

Try this routine for a healthy aquarium:

Every Day

Check that your equipment works properly (filter, air pump, etc). When you feed, watch the fish behavior. Health issues can be caught early by seeing behavior changes.

Every Week

Take a head count. If a fish dies, it can decompose very fast, especially if it was small in size. This can raise your ammonia, nitrites and nitrates. Remains should be removed as soon as possible.

Every Other Week

Run water tests for pH, nitrites, nitrates and carbonate hardness. Change around 10-15% of your water. Use your vacuum on the gravel to remove wastes. Clean the aquarium glass. Filter floss works well, or you can buy special scrubbing sponges to remove algae. NEVER use a grocery store kind of scrubber, these will kill your fish. If you start from the bottom of the glass and work upwards, you can minimize the amount of algae spores that enter the water. Rinse your cleaning material often. Use the water you removed from the tank to rinse your filter cartridges.

Every Month

Put in new filter cartridges, inserts, carbon or floss. Check all your tubing, airstones, connections, skimmers and other equipment. Do a clean up on the aquarium top so you know your lighting is not compromised. Check for expiration dates on all of your aquarium supplies. Don't use supplies that are past their dates. Tests can give false readings if they are past their expiration.

Happy fishes!

If you want to read more about keeping a fish tank in your home, visit me at http://www.thefishtankplace.com

About the Author

Rebeca has been interested in animals and Feng Shui for many years and now she wants to share her knowledge of these subjects with people in a very light and personal way. Feng Shui has improved her life in many ways, and her cats and dogs, and the fish that came as a part of her passion for Feng Shui, are now a very important part of her, and she's very happy to share her experiences with everybody.