My tank has been up and running since the first week in January. The last month or so I have started getting a lot of red slime algae. I thought it was coralline at first but nope it's red slime. I had a cheap Aquatop skimmer that I replaced on sunday with a reef octopus bh100ss. I also have a HOB filter that I put Cheato in yesterday with a homemade light box on top of the filter. It's a 55 gallon tank with no sump. About 50 lbs of live rock. My ammonia, and nitrites are at zero. My nitrates are between 5 and 10 ppm. Haven't checked my phosphates yet. Don't have a test kit for that but plan on getting one tomorrow. I do a 10% WC every weekend and have always used water from my RO/DI. I was feeding way to much so I have cut back to a half frozen cube every other day. Also cut back on the light times. I have 6 fish. Coral beauty, two clowns, royal gramma, six line wrasse and a valantini puffer. One Sally light foot crab. Put five snails in saturday but the puffer will take those out soon enough. Any ideas what else I can do to help get rid of the red slime ? Sorry for the long post but trying to explain what's in my tank and what I've tried so far.