Did you try chemiclean or cyanokill to make sure it wasnt cyano? Im not sure of the source said:
You are always incredibly generous, thank you. I still want to buy your DSA cube when I have the funds sir. I have confirmed that they are indeed Dinoflagellates and not Cyanobacteria. They are stringy, brown, and love to grow on SPS tips. I have added more flow and done lights out for 48 hours. I read a 29 page thread on RC that it "just comes and goes" and "water changes can fuel this". I have read of people using up to 4X the recommended dose of Peroxide with no luck...but I have been dosing it daily for almost a month now. Lights out works like a charm for about a day, but these Dinos are like sand people- "They'll soon be back, and in greater numbers." I love reefing, so I'll continue the battle, but geez...I just wanna enjoy my tank.