I am also having a cyano problem. 3 months ago i thought I was the only one and was thinking my biopellets weren't doing the job. Swapped the biopellets with GFO, changed my DI resin, swapped out my old MH bulbs (about 3 months old), and did water changes every 2 weeks and then tested my phosphates and still got a .02 reading. Had a few sps colonies brown out or completely bleach. I will change out my rodi filters and see if that makes a difference.