Question about the reef floor


New member
I'm deciding on a substrate and was wondering what would be most natural. I'm deciding between a sand or crushed coral substrate. Is the floor of most reefs composed of sand? Are there any areas of reefs (in nature) which have a floor composed primarily of crushed coral/small shells?


New member
the natural reefs ive seen are a little bit of both CC and sand. most people dont use CC in a reef tank because waste can collect in it more than a smooth surface like LS.


Recovering Detritophobe
It depends on what reef locale you are going for.

SPS come from areas of high flow. This high flow blows away all fine sand, and all that is left is crushed coral, of if the flow is strong enough, rubble.

Many LPS come from lagoonal areas with slow flow. The sand here is finer because silt can settle here in the low flow. Consequently, LPS have evolved much better self-desedimentation processes than SPS.