I'm trying to decided how i should proceed. Ive been fighting cyano for months now, starting to think my rock might be leeching po4 as i can siphon it off rocks and is back next day. got tons of flow, literally, 150 display with 3 mp40s running about 90% plus return pump. I do weekly water changes, nothing seems to help. po4 on tests is low, i think its just being used up faster than i can test. wanted some opinions on my plans, never been happy with my aquascaping, i have some rock that i bleached/acid bathed. thinking about doing a total rescape with all new rock, while i do this put my live stock in qt for a couple weeks. if i do should i keep a couple pieces of my current rock in the sump for a while? do I sound insane? Just not sure what else to try.