Hi. A couple of months ago I started having some trouble with my fish tank. Due to some ich medication I was not able to use skimmer for quite a while, and that's when the troubles started. A very resistant algae developed not only on rocks, shells, but also on or close to corals. I've put a baggie filled with phosban but it doesnt seem to be helping the problem. I try to remove the algae manually as well but it's a hassle and always possible. Any ideas?