[NATIVEVAMAN]

If you intend to build a reef tank with live rock and coral you should consider useing a protien skimmer instead of the wet /dry system as they are much more efficient at removing all the dissolved waste that has to go to provide an acceptable enviornment for fish and corals.One of the reasons to have a refugium is to provide food for fish and remove nutrients from the water. Since this is generally done best with slower moving water a refugium would work best when it is a seperate element from the sump either sitting on top of the sump or above the sump outside the cabinette.This way the skimmer can be bypassed and go directly to your return pump area allowing the pods from the sump to go directly to the tank.No sense in growing all those fine critters just to have them end up in the filter.If you do decide on a skimmer they all have a minimum depth and that depth is different for each skimmer.Also you need extra room in the sump to hold all of the return water should pumps fail.A 30 gallon sump should be fine but if you have room for a larger one you should consider it.I will be useing a 40 gallon for a 65 gallon tank,water volume is key here. More water equals more tank stability.