Agree with Fluff, definitely cyano
prevents phosphates from being introduced during water changes (assuming your salt mix is phosphate free). It doesn't help if you're over-feeding, have a high bio-load, or don't do frequent enough water changes.
I came to SW
from the FW
planted tank niche of the hobby...so when I learned that phosphates caused cyano
, I assumed 'high phosphates' meant 2ppm or more.
0.1ppm is more than enough for cyano
Get yourself a test kit, and see what your levels are. Either SeaChem or Salifert brand. I would test your RO
water too, especially if you get it from a grocery store...they likely need to change filters and membranes if the RO
tests positive for phosphates.
Skimmers can help reduce phosphates, as can adding macro algae to a sump or fuge (and even a few types can go in the display tank). Good luck