I've been fighting zero nutrients in my 40 breeder since it was set up a year ago by dosing po4 daily and no3 weekly. I still can't keep sps and have pale corals from time to time because it's very hard to keep nutrients up regardless of how much I feed. However, in the last 3 months I've begun to get what I believe to be turf algae all over my sandbed and increasingly on my rocks, making matters worse. How do I get rid of this stuff so I can at least get an accurate reading of my nutrients and try to keep my corals fed while I look for more fish? It grows back very quickly along the sand even with siphoning it out every water change.