I do have Carbon in the filter. I put it in there about 3-4 weeks ago.
I use Flourish as the Fert/Additives. 1 capful of Comprehensive, Excel, Potassium, and Iron after each 30% water change (2x weekly).
Substrate is a mix of Gravel and Flourite, probably 70% gravel and 30% Flourite.
And just in case, my pH is 7.0, and KH is 5.5. Co2 is 17-18ppm. GH is 6. I have Crushed Coral as my GH increaser.
It is "possible" that I have too many fish. I have 5 Corys, 4 Botia, 4 algea eaters, 2 Killies, 1 Ram, 1 Rasbora, 1 Neon, 1 Z Danio, 4 Gouramis, and probably 1 or 2 others... the 1's weren't intentional, they are just the only survivors from the initial cycling of the tank &/or my wild pH swings when trying to perfect the art of DIY co2... now I have pressurized and nothing is dieing, go figure!
What affect do the fish numbers have on PO4? Does waste cause it? Could cleaning out the filter more often have a positive effect?
450g Planted Discus Tank - Work in Process!