I have a 29 gallon, just switched to live plants (hopefully they survive :)) I do a 50 % water change every week, and all of my params are good. Current stock as follows:
5 platys (2 panda, 2 red tail dailmation, 1 bumblebee)
6 black phantom tetras
4 bloodfin tetras
2 spotted cory's
1 german...