I haven't posted in here in a while, but I am battling high nitrates. I have thoroughly vaccummed the gravel, rinsed out the filter media, and have done 50% water changes and nearly stopped fertilizing my plants (only dosing at wc). I have 2 HOB filters (Tetra Whisper60 and Aqueon 55/75). My normal wc is 25-50% weekly. It seems like the plants are taking off quite well, which is why it suprises me that the nitrates are still so high. My last water change was on Sunday and I checked it this morning and it already 40ppm.