I'm at my wits end. I've been having high nitrate problems since Feb 2012. I don't know what to do anymore. I've called LFS I got my fish from and I keep being told to bacteria supplements in it. Or to put a double dose of prime in the tank then do a water change in a day. I've been told not to do more than one water change in a month. I've done everything that's been suggested and the nitrate stays high. My water conditions are: Temp- 80 degrees, Nitrite- 0, Nitrate- not sure. The color doesn't match any color on the chart. So I'd say between 40-160. As far as ph I didn't test for that. I have a 20 gallon tank. I have 7 fish in it. 1 sucker fish, 1 black phantom tetra, 2 neon tetras, 3 platys. We have had this tank set up since December of 2010. Always have at nitrate problems but this is the worse it's been. Help please. We have had endless fish die and I'm guessing this nitrate issue is the problem. All the fish we had die have been mollies and guppies. Forgot to say my Ammonia- is between 0 and .25. Ammonia has always been this way.