i misread your post i use peroxide to do the test to make sure it was cyano. Have not done any Peroxide dosing. My 3 Day Black out is complete tank looks great. No more Dinos. I understand they are still present but with my strict cleaning prior to the black out, running GFO aggressively, lowering my photo period and feeding less maybe i can help hinder it from coming back. All fish were fine and Corals look great. Blasto has 2 new heads i did not see prior to the blackout. And best of all sand bed is almost white again. I'm going to syphon some of the dead algae and off the rocks and do a 30 gallon water change. I'll change out the GFO and Carbon. Clean the skimmer and change out the filter socks.
Hopefully i can now keep the tank clean of algae for the most part. Tested the Phosphates with the Hanna Checker and it was: 0.025