I have a brown algae growing on the surface of my sand. Have sucked out the top layer of sand when doing a water change but it grew back. I also cut back the lighting from 10hrs to 8 hrs. It seems to be growing just in the sand. All parameters are good nitrite 0 nitrate 0 ph 8.2 ammonia 0 alk 2.0 It is a 29 gal bio cube with multiple corals, clean up crew, crocea clam, and one fp clown and one orange spotted goby. I feed the fish once a day alternating mysis shrimp and pellets. When the lights come on later ill get a pic up.