the skimmer i have is a coralife super skimmer and boy does it put out! i love the thing's efficiency, but the ph that is used to run it is pretty big in my 20g tank. the ph size is the only downside to the skimmer. i use a fluval 204 canister for my other filteration, and what is between the inlet and return for the filter is my heater. the rest of what is in there is lr and fish.
im thinking about upgrading to a 46bow anyway. then i'll make this tank a sump/ref. and keep the skimmer and filteration in there. that way the only thing that i'll have in the 46g is the overflow box and may be a ph for water movement.