At the moment the tank is a bright green on the rocks. Too much light?? 0.12 PO4 is with a Hanna checker. Nitrates of 12 to 13 also with Hanna. I have s small clownfish, a blue tang and an Eibli Angel fed each day with 1 or 2 cubes, alternating mysis, brine shrimp, micro plankton etc. Maybe I could reduce the feeding?? Is my problem simply nutrients? If so how can I get them down further (yes, RO water - 10% change a week - my LFS said to give up changes for a while)? A dozen snails, 2 hermits and 3 shrimp. I still do not get whether I need more or less light…. Thanks for taking the time to help out.