The weird thing is after sun down the tanks starts to look better.

Marc Levenson wrote:
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?