Sponges are filter feeders and appreciate a well-fed tank. Phytoplankton supplements and other small micron sized foods can be carefully dosed to keep them happy. Moving detritus into the water column with a turkey baster or small pump is very beneficial to sponges. Some sponges like to be on top of the rock and others prefer to be on the bottom. We will package the sponge rock oriented in the manner as to which it was harvested from the ocean bottom for your reference. In general, higher flow, low light, nutrient filled water.