i have a 20 long tank with just a couple of sword tails, dolmation molly, and spotted cory's. my tank has been running for 3 weeks now with a piece of drift wood that had started growing little white spots around some areas. after doing some research i think that it is a decaying matter of some sort and i took it out completely and replaced the area with some stone slabs that i found outside and boiled them for like 15 hrs. this was done on 4/12/12. since then things have been going aq little bit more smoothly i have been doing everything to try to raise the PH NATURALLY ( throwing in some ferns and java moss, i have done one 25% water change with a gravel vac) both my nitrate levels (NO2- & NO3-) are perfect, but the ammonia levels are a little high around 2.0 ppm and the pH went from 6.0 to around neutral - 7.2, can anyone help me with trying to get a steady levels with in my tank?