Closed Loop Via Overflow Bulkhead

[Mtinrunner]

I can't seem to find the answer to this question. Hopefully someone can help me? I have two 1.5 inch ID bulheads, one in each seperate overflow on my 300 gal. Using Stockmans or Dorso standpipes I'd like to run one overflow through my sump with skimmer at about 1000 gal per hour and hook a closed loop up directly to the other Overflow with four returns in the tank. Anyone see why this wouldn't work or do I have to pump it out of the sump? Thanks

[fishfreek]

Ideally the closed loop intake would be fully submerged so as to limit the potental for air intake into the closed loop. I would worry that air would be going into the closed loop all the time via the standpipe. This would cause microbubbles to be expelled out the returns. Of course you can always try it and see how it works out and if it produces results you dont like you can just plumb the second overflow into the sump and pump the closed loop out of the sump back to the tank. Although it wouldnt nessicarly be a closed loop then.