I wouldnt say Im ULNS, but I run a skimmer, sump and fuge. 75g with 8 fish, and a mix of corals including numerous sps. I have 3 bags of chemipure elite in the sump. Ammonia/nitrates/nitrites are 0. Phosphate...trace amounts. With a salifert test kit on double sensitivity I get a 0 reading, but it really isnt a low phosphate range tester. I suspect I have trace amounts because I have to clean my glass every 3 days or so.