can the cyano alage kill your live rocks and or all your coral?
Well, I've had cyano in my tank before, but not very much. I suppose if it got thick enough it could choke out things on your LR and coral. When I had my little outbreak, I sucked as much of it out of the tank as I could with a turkey baster, and the clean up crew (snails & hermits) took care of the rest. I'll bet when you start using the RO/DI water it will help. You could also have a water flow issue (dead spots) and possibly other problems with the chemical balances of your water. Since you've already taken steps as far as inverts and flow, use the RO/DI and give it some time.

Wendy