My 75g tank has had high nitrate levels for a while now..... . Some of my acans are slowly dying I think because of it. The levels are between 60-80 ppm. I did a 40% water change a couple of months ago but that didn't seem to work..I also cut back feeding to try to help. I have a 10x10 screen with 4x 23w cfls that I change every 3 months. The screen seems to be thriving the best I've ever seen it. My bio load is 90lbs of live sand, 175lbs of live rock, 20lbs of crushed coral in sump and 14 fish. I run the lights on the screen 18 straight hours now, would running the lights 24/7 help get rid if the nitrates faster? (I would have put pics up but can't log into site through tap talk.)