Tank bubbles and cyano during day

[JohnSiesta]

I tried this query on the Lighting/Filtration thread and didn't receive a response. In December I switched MH bulbs from a 20k to a 10K and my return from a 301 powerhead to an 802 (my sump->refugium->display tank are on the same level). Since that time I get a daily dose of cyano and micro bubbles all over the sandbed and LR. Then I have to clean everything daily with a toothbrush and powerhead which is kicking the deterius all over the place. My testing hasn't shown any phosphates or nitrates in the system.
Looking for advice.

 

[JohnSiesta]

Also, I only see this during the day cycle with the MH, making me wonder if the higher light intensity is changing the reef chemistry.

 

[Randy Holmes-Farley]

The bubbles are O2 from cyano and algae. I'd look to ways to decrease them (reduced nutrients (nitrate and especially phosphate), reduced organics (skimming, carbon, ozone), and more flow) and the bubbles will follow.

These articles may help:

Phosphorus: Algaeââ"šÂ¬Ã¢"žÂ¢s Best Friend
http://www.advancedaquarist.com/issues/sept2002/chem.htm

Nitrate in the Reef Aquarium
http://www.advancedaquarist.com/issues/august2003/chem.htm

Iron Oxide Hydroxide (GFO) Phosphate Binders
http://reefkeeping.com/issues/2004-11/rhf/index.htm

Organic Compounds in the Reef Aquarium
http://reefkeeping.com/issues/2004-10/rhf/index.htm