I have a brownish/red algae that is growing all over my sand and LR. My tank is about 5 months old and I have been doing water changes every 2 weeks using sw from my lfs ever since this problem started occuring about 1.5 months ago. The problem persists and at times it gets so thick that it will start stringing up in a few areas. Its only a 29 gallon tank. Does anyone know preventitive measures to reducing growth or eliminating it?