The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Well as long as you have good enough circulation on the main tank and do not need the extra water flow then you can put just about everything in your sump. My main tank has nothing but my over flow box, spray bar, sand, and rock.
Well...you didn't specify the size of those powerheads....but 2 of them sounds pretty good in a 40 gallon. Plus...you would have flow from the return line of the sump.
So it sounds to me like you've got enough tank circulation and that all other filtration stuff can go into the sump.
You can put the heater and the hangon in the sump with out much problem. Other things you could have in the sump include an autotop off system, a skimmer, a UV unit, a calc reactor, etc.