after having a dsb of agronite in the 90 i opt for bb this time round with the 120. Seems good so far. all the water tests check out great and the tank cycled faster then it did with the dsb. I painted the bottom black from under to keep the light out from the fuge. It is a chore to clean though if not kept up on. But i like the way the rock looks sitting on the black bottom glass. I dont see coraline growth on the bottom either. Will be nice though i hope when it dose grow.