Because you started with dry rock, your biome isn't as diverse as it would be with live rock. Other than adding actual live rock the best way to increase the bacterial diversity is to add live sand to your tank or sump. If you have local reefers with successful SPS tanks see if you can get a cup of sand from them and add it to your tank. Another fantastic source of live sand is Indo Pacific Sea Farms (
www.ipsf.com) Get the mix and match special and include the Wondermud, Liquid N reducer and Live Sand Activator. These are all collected locally in Hawaii so the bacteria are from the Pacific Ocean. If neither of these options work for you then a variety of bottled bacterias will help. My favorite are the Prodbio products, but they are not widely available here. MB7 Dr. Tims, etc will do in a pinch.