You really shouldn't change the water and disinfect everything, it messes up the cycle and does more harm than good. What you should do is buy a test kit for ammonia, nitrite, nitrate, and ph. No testing strips, only liquid test tube kits. Here's a good article about the water cycle, its not long and I think its very important to read through. http://www.aquariumadvice.com/articl...q=2&fldAuto=21