I would try stirring a little bit of the sand every day (plastic rod, kabob skewer, your hand). Corals will appreciate the release of bacteria and other possible micro life.

How about vacuming the sand. Or changing out 1/3 of the sand.

If we rinse the sand, try to do it in water change water.

When putting new dry sand in a tank it should be placed in saltwater for at least 24 hours prior to placing in your tank. This will prevent a large drop in Alkilinity. This short aging of the sand grows the bio-film on the individual grains of sand.

My personal preference is a Remote oolitic argaonite deep 4 -6" sand bed and 1 inch SB in the display, Just my opinion. There are many ways to keep a reef tank.