My personal experience with
cyano might be helpful.
I battled a serious problem for nearly 1 year. The only way I could keep the system alive was to carefully siphon off the
cyano and do water changes nearly daily while I attempted one cure, then another.
I cut back on feeding...which has cost me a number of detrivores, and seriously hurt my sun coral.
First, I checked Phosphates. I could not detect any, but used various phosphate removers and
AC for a time without effect.
I replaced all the filters in my
RO/
DI equipment. No effect.
I replaced all my lights, including my
MH bulb which was only 8 months old. No effect.
I desperately experimented with various
cyano remover chemicals like chemi-clean and red slime remover. I do believe that the red slime remover actually had an effect, but it was very short term.
I began aggressively vacuuming (sp?) my sand bed. (Which turned out to be pretty dirty!). This led to the eventual complete removal of the sand bed and plenum that was in my sump. No effect. (as a side note, I did discover than my sump sand had clumped and was making it difficult to maintain
Ca/
Alk/
Mg levels)
Finally...I made the big financial decision to replace my Prism Pro with a Euro-Reef CS6-1 skimmer. I thought that the Prism Pro was working fine. I certainly had to clean it regularly. My system is maybe 40 gallons, so the CS6-1 seemed like pretty excessive skimming. Whamo! Overnight removal of a problem that lasted nearly 1 year!
That's my experience for what it is worth!