Ok, I've been reading the forums, and I've come to discover that I have done many things wrong. I have a 55 gal tank, that my husband and I set up last Sunday. We had all of our fish in there by Monday afternoon. As of now, the Nitrite, and Nitrate are at 0, the ammonia is at .25, the ph is around 7.8 I haven't done any water changes yet because at the pet store they said I didn't need too...but my tank smells a little like (sry no other way to describe it) cat urine whenever I open it to feed them....what can I do to get rid of the smell, and what is a siphon? I read here that you need one for the water changes, I have a gravel vacuum, but the lady said all I had to do was suck it out a little, is this recommended? Sorry for all the questions and thanks in advanced for all the help