My overflow keeps loosing syphon.. not sure if it has something to do with how I start it or the size.. I'll go through my whole setup just so that somebody may understand what's going on..
I have the skimming type pvc syphon explained in the 101 thread, I built mine out of 1.5".
In my sump is a RIO 2100 pumping into 1" pvc although it gets bottlenecked to go into a UV filter at 1/2" flex tube. This goes up to the oppisite side of the tank of the overflow in a 1" pvc with holes every so often.
My tank is 180 gallon.
The way I start the syphon (not sure really how I should given size) is stick a hose into the overflow and turn it on with my hand held tight around it so all the water goes into it, seems to work. has pretty good suction after that. Only problem is, I've crafted a sort of grid out of a pvc cap and dremmel (love that dremmel) that will keep the fish from jumping into the overflow. Once the syphon is started I put that on the pipe and the syphon weekens significantly, after awhile it's not putting as much water in the sump as my pump is putting in the tank, the water flows over the overflow, then syphoning stops..
!!!