Adjusting life sand volume to make up for lack of liverock

[syncro]

Based on what I've read, this sounds like a lightly stocked tank so you should be fine. If you find you are having problems the next step would probably be a protein skimmer.

If you want to go the less conventional route I've been looking into deep sand beds (DSB). These are typically 4 - 8 inches deep either in your display tank or in a sump. Ron Shimek is a proponent of DSB in your display tank. He has a forum on at marine depot. The other person I've read about is Anthony Calfo, a commerical coral farmer. He advocates aggressive skimming plus remote DSB (in sump). Check out DSB in a bucket for nitrate control at ReefCentral.