It won't hurt the bacteria in your rock. In fact, it will help the rock from getting all clogged up. You basically want the live rock to be fairly aerobic, so if there is a decent amount of detritus, the oxygen gets consumed fairly quickly. Hope that helps.
How often, if ever, should the sediment be blown off live rock with a baster? Blasting the top sends sediment out from all sides though all the inter-connected holes. Is this hurting the bacteria that inhabits the rock?
