the amonia will change into nitrites, then into nirtates, but waterchanges are ALWAYSE necessary. I think that all those chemicals, and stuff you buy in a bottle to speed up the cycle, or rid your tank of amonia are a waste of money, and only for the lazy and caresless. Now that being said, this is not you (lazy or careless) because your still cycling! after your tank cycles, if you take care of it, you will not need things to lower your amonia and such. Just wait it out, and don't add anything until you are sure your cycle is complete. I'm about 3 weeks into my cycle, and i'v been really lucky and i think (hope) it's almost complete, and my nubmers are looking really good. I read somewhere that for a tank as large as mine (120g) i need only to do a 6g water change a week.....thats so easy! so what i'm saying just keep up with your water changes. good luck. let me know how it goes and we can compare notes since we are about the same length into our tanks