[quote name='Flippin'thing bit me eye' date='Sep 19 2003, 11:06 AM']Brown algae occurs if the tank does not recieve enough light, trust me[/quote]
I agree that that is 1 possibility but not the only one. Low levels of oxygen is another plus an excess of nutrients, silicates and silicic acid.
I would increase lighting tho as it could be the problem. Also, use a silicate adsorbing resin in your filter. Step up the water changes to at least once-twice a week and one of these solutions should help the problem go away. Then I would keep the lighting on more often or buy a new one and see if it stays away. If it comes back, then it's another possibility. This way you can troubleshoot the problem.