sandbed/algae/nano issues - take your pick.

[Myka]

New sandbeds are prone the clumping because they are not in equilibrium to the water and this may cause precipitation of calcite. Do you vacuum the sand bed? Of not, I'd start. The bright green growth is likely cyanobacteria. I think if you start weekly vacuuming and blow off the rocks with a turkey baster daily, ams you should be in good shape in a few weeks.