If you are cycling with fish, then yes, do those water changes. It may slow down the cycle, but will help reduce stress on the fish. If its a fishless cycle, then don't, wait till the ammonia and nitrIte, drop to zero, water change and add fish.pcam86 said:If my tank is still cycling is it ok to do a water change every 2 days being as i have hight ammonia, nitrite, nitrate and PH?