Tank is 130lt (32 us gallons) Tanks around 3 and a half months out I'm using a fluval u3 filter, medium size sponge filter, as of yesterdays water test 0 ammonia, nitrite and nitrate, gh is 16, kh is 12, I have 11 platys, 12 otocinclus catfish, 3 shrimp, fairly well planted with co2 injection...