I have a 29 gallon reef tank with mostly zoos and other soft corals. I started off with crushed coral as the substrate but then put sand over it. I've tested for all the major things, pH, ammonia, nitrite, nitrate, SG, etc. I have a major problem with algae. All kinds, hair, bubble...and diff. colors, red, green, brown...also some of my corals will not open and I don't know why. I have a skimmer also along with carborn and mechanical filtration. I've tried getting sea stars to clean the bottom but they never last more than a day. When I do water changes I siphon out the bottom, but there's so much rock covering the substrate I can't really clean enough to make much difference. Any suggestions or questions?