Glad to see your back into the swing. Amazing corals you have. Now just a bit about my tank. I had the same problem. I know you guys here dont like additives you cant test for but this is what i do. I use my phosban reactor. I know some have problems with it but i seem to do well. I also use something called marine tlc. Its basically nitro bacteria but its amazing stuff. My hair, bubble, dictoya and all other algae disappeared in 6 wks. And I slacked recently about adding it monthly and i got the red slime on my corals as you got. Started adding again and poof, gone. I have dsb and lots of lr not cooked. Just some info. That and weekly water changes does me good. Oh, and cant forget my yellow tang. Hes the bomb.