overflow question

so i am a really big fan of diy, i have a homade overflow, and i just bout a mag 7 utility pump that i have in my homeade sump out of a 40L. anyways my overflow has 1 inch pvc pipe siliconed in a u shape witha hole drilled and one of those threaded hose adapters that i suck the air out of (mouthful of salt water spit out almost every time /DesktopModules/ActiveForums/themes/_default/emoticons/crazy.gif) and plug with a suction cup, pretty good deal for a 12 dollar overflow. anyways i want to put the pump on all the way, i have a ball valve going up to my tank.  its about three quarters of the way open. any ideas on how to make it go more water faster, maybe add a second one, (two mouthfulls a water every time /DesktopModules/ActiveForums/themes/_default/emoticons/sick.gif)
thanks for any help