I have clumpy, little balls of green algae in my tank. I only find them in the sand bed. No other nuisance algae anywhere in the tank. I scoop out piles of little algae balls and then find more of them the next day. Should I just go bare bottom for a while or what? Pretty frustrating. Tank chems are pretty much perfect and i'm not what i can do to improve water quality. I have plenty of clean up crew too.