My tank has had high nitrate levels for the last few weeks. I've done just about everything I can think of, but they wont go down. I've done multiple 30-40% water changes, thoroughly vaccuumed the gravel at the bottom, used Amquel and started using plants. I've had high levels in the past, but they would usually go away after a water change or two. Normally I would continue to use the Amquel, but the last time the fish became very stressed. The other odd thing about this is that the nitrite levels are very low. I've noticed that either they will both be elevated or neither will be. Any help would be greatly appreciated. And just in case it helps, it's a cichlid tank.
Thanks,
Brendan