Hi there aye have 8 foot 264 gallon tank with 2 fx6 filters aye have 3 plecos 3 Oscar's 2 dempseys a devil and 2 jags and 2 blood parrots. I had a problem with ammonia in my tank what aye have resolved now but cant seem to get my nitrates down everything else is fine now my parrot laying on bottom of tank breathing fine just not himself so is my devil and Dempsey cichlid any ideas aye do half tank water changes weekly and youse sechem prime as a conditioner aye have tried double dosing the tank aswell not changed anything my fish are all large do you think it is too many fish and my filters cant break down the nitrates quick enough any ideas