garyd

I've heard everything from every two weeks to every two months. I have a 180 gal tank. I do about 15 galions every 6 two months and I refill about 5 gal a week do to evaperation. I have about 15 fish, two Blue shrimp and two placastumusses (suckers). My tank is two months old and my fish are small at this time 2-4inches mostly 2 inch fish. I have safe amonia and Nitrites and nitrate is .40. sound good? Anybody?

Gunnie

Your bio load may be small, but it's hard to tell unless we know the species of your fish, and if your fish are all young, your bio load will continue to increase until they reach adulthood. If your nitrates are already that high with small fish in it now, I would suggest you get into a routine that would keep your tank healthy once the fish are full grown. If your tank is cycled, the amount of water you change out every water change makes no difference. When you say your ammonia and nitrites are safe, they must be at zero to be safe. A cycled tank will have zero ammonia, zero nitrites, and some nitrates. My largest tank is 100 gallons, and I do at least a 50% water change on all my tanks except my 10 gallon. More is better. If you are able to do weekly water changes, then I would do it. Your fish will love you for it, and they will have more growth with the cleaner water. If you don't already have one, I would suggest you purchasing a python to clean that large tank.

http://www.pythonproducts.com