Was just wondering if you ever got it working...it looks like your using the "Pipe Siphon". At the tail end of you drain pipe you have a 90 angle going straight down into your return pipe to your sump or fish tank. If your siphon "Fires" but doesn't reset after the GB has drained, this is where mine is different from your set-up. I'm not tiring to drain into a pipe but straight to my fish tank. I think that your last 90 needs to be turned up just about 50 degrees from pointing straight down.

Maybe you could use a rain gutter as a return pipe back to your sump or fish tank.