Plumbing

I've recently installed a weir type overflow on my 100g mixed reef, and due to some extenuating circumstances I wasn't really interested in even spending the $15 or so to pick up something along the lines of an aqualifter to pull air out of the device to keep the siphon going. My initial thought was to just run some airline from the nipple on the overflow down to the sump and just manually start a siphon and let it run. . .life is happy, right? Nope. I have a 2100gph flow powerhead right next ...