Have a 6-7 inch dsb with the top 2 inches Fiji Live sand and the bottom 5 pink samoa sand..Also have about 5 inches deep in the refugium with the only flow coming into it from the output of my skimmer. Tank has only been up about 4 months now but I feed heavily according to some..At least once every other day..Brine, bloodworms,krill,micro algae, formula one and two..I have 3fish, purple tang, blue hippo tang and a flame angel..About a dozen crabs and dozen and a half snails along with one orange star..I test my nitrates and they don't read on either kit..Salifert and Seatest.. Only due about 4 gallons water change a month..Waiting for the tank to age alittle before adding any stonies...Otherwise everything looks very good..