No, this isn't a bulb issue. What are your nitrate and
phospahte readings?

Does this brown algae act like a layer or film on the sand.
Can you scoop it together so it looks wrinkled in a pile?
You might be dealing with Cyano bacteria, which does what
you've described when the lights are on, but virtually
disappears when the lights are out.

Marc


Joe Cool wrote:

I have been having a brown algae issue for about 4 weeks. I am now on
vacation and was here when the lights came on at 10:00am and noticed the
algae was completely gone from the rocks and about 70% gone from the
sand bed. I come back about 4 hours later and it is as bad as ever. I
have a 24" corallife agualight deluxe double 130 watt power compact. It
bought it in September. It comes with one 65 watt Actinic and one 65
watt 10,000K bulb. I have a windows next to the tank that I have had
blocked off with a rub so no natural light hits the tank. My question is
should I replace the bulb even though they rate to last for 12 months?

--
Personal Page:
http://www.sparklingfloorservice.com/oanda/index.html
Business Page: http://www.sparklingfloorservice.com
Marine Hobbyist: http://www.melevsreef.com