I am currently working on a 20 gallon nano. Do most of you run hang on the back filters or no? Also as far as lighting I'm looking at 2 15w ABI par 38's or the 30w hibargero light. Any preferences? It will be mostly a ZOA tank. Eventually I will add some encrusting montis, and a few sticks. I have been out of the hobby for about 6 years.