The sand needs to be a properly maintained DSB in order to have any bio-filtering capabilities. There is definitely more zooplankton in tanks with sand though.

Mindy. What is properly maintained. Is it more than cuc

Bare bottom and i LUV it...with a mosly sps reef the sand would be flying.And if some acro frag falls,it's not dying on the sand.

you need a working DSB, which is pretty much impossable. we cannot sustain in our tanks what it keeps to properly maintain a DSB so you eventualy have problems.

Steve