Cyano baffles me

[Delphinus]

Just occured to me that when I said "NO actinics" - it's looks like I said "no actinics" but what I meant was "normal output actinics". Ooops. From now on I'll use periods in that particular acronym.

Anyhow, if the lights are over a year, that might explain the difference. But, if you're just growing chaeto and the lights are growing the chaeto OK and if the cyano isn't anywhere else, I'm not sure I'd jump on replacing the lights, unless I wanted to do so anyhow.