Cyano Help !!!!

cjrudy · Nov 20, 2011

Six month old 90 gallon reef tank and terrible cyano outbreak in my sump and on the sandbed. Nitrate and Phosphate levels are at 0 and I have great flow including an MP40 and Koralia 1050. Looking for causes ?

One possibility is lighting, I purchased a used TEK fixture six months ago with six Geissman bulbs which are probably at least a year old. Maybe time for a change?

Second could be water, I use RO/DI but I have not changed my filters in almost a year, the TDS always reads zero even though the water pressure has dropped to 30. I just ordered new filters from BRS.

Third could be over feeding, but I only feed once a day as much as they eat in a few minutes.

Seems like I have eliminated almost everything, any suggestions.

Reef UP · Nov 20, 2011

Well your tank is most likely ready zero on no3 and po4 because the cyano is causing false readings!
You could pick up some microbacter 7 or some microbe lift special blend also do a 5-10percent water change daily for a week, and yes I'd change out your bulbs they could be causing a little bit of the problem as well

donfishy · Nov 20, 2011

what kind of skimmer you have?

cjrudy · Nov 20, 2011

Swc160

jlemoine2 · Nov 21, 2011

Reef UP said:
Well your tank is most likely ready zero on no3 and po4 because the cyano is causing false readings!
You could pick up some microbacter 7 or some microbe lift special blend also do a 5-10percent water change daily for a week, and yes I'd change out your bulbs they could be causing a little bit of the problem as well

+1 on this. However, I think excessive nitrates and phosphates are more likely the cause than old bulbs. What test kits are you using to read phosphates? I doubt phosphates will be at zero, but most test kits commonly available to us are not accurate enough to read as low as we need.