I'm loosing the war with GHA, help?!

[marie]

Originally Posted by andrewsk

I agree that direct sunlight could cause the problem, but what is the algae feeding on to make it grow?

She has a fair number of fish in the tank and once a pest algae gets a hold it needs very little in the way of nutrients to thrive.
I have always had shallow sand beds that I never disturb and I have never had problems relating to them

[marie]

As an example of how an algae can take over in a low nutrient enviroment. this is my tank last year just after i transfered everything over. I had left it fishless for 8 weeks, no food added to the tank at all, new sand bed, 100% new ro/di water (didn't use my old tank water), all the rocks were rinsed very well in the old tank water before moving (so there was no detritus). And still, this brown macro algae that I didn't even know I had, took over my tank. This pic was actually taken after the fish had been in there for a few weeks grazing on the macro. It looked even worse before