Looking for Guidance- Cyano in Sump

[reefbyremote]

My reef is 90 g with a 30 g sump. It is 2 years old and mainly sps. All is going well in the reef but over the past 2 months I have started seeing cyano in the
the sump in the centre refugium chamber (which has about 2 inches of sand and a little rubble rock as well as chaeto.) Cyano has never appeared in my system before. The return pump is a aquarunner 2500 and I am running multiple powerheads in the main tank. I am also running gfo in a TLF reactor using a small powerhead in the sump.

Any ideas on my the cyano is limited to the sump? I presume it is a lack of flow issue or lack of clean up crew? I could increase to a larger return pump or installing a powerhead but would appreciate your guidance first.

Also what does everyone think about dumping the refugium, at the very least the sand in the refugium?

Thank you

[reefbyremote]

Anyone?

[cwatkins]

Bulbs could be getting old?

Try a black out for a couple days see if it goes away, and then if it comes back.

[reefbyremote]

Thank you for the reply.

I changed my refugium bulb one month ago. I am using a 6500 daylight bulb as recommended on the Melev's reef site. I will change it again after a couple days black out and see.

I have also read that any FEO leaking from my reactor could contain phosphates and obviously iron, the two things that I understand cyano may need. This could have been the case as I recently changed the FEO. In the meantime I have cleaned out the cyano and went to a slightly more powerful return pump I had on hand, a eheim 1260, to increase flow.