If you have a 1" drain bulkhead on the wall of your tank near the top, there is something you can do. Basically you run a 1.5" X 1" tee off the bulkhead; the 1" side going into the bulkhead from outside the tank, one of the 1.5" sides going down (drain line to pump input) and the other 1.5" side going up. To that side you attach some elbows so it goes up and over your tank, and down into the water. MAKE SURE you put a strainer on it, or you'll suck animals into your pump. Anyhow, when you start up the pump, you'll create a vacuum in that part of the plumbing which will draw water up and over and start the siphon. Viola; you now have a 1.5" drain, fed by the elbow and your 1" hole.

BTW, when you say return, what is normally meant is the pump output returning to the tank. If that's the 1" hole you're talking about (I don't think it is) you simply add a few 1" outlets from the pump to reduce the line friction. To get good flow from the sequence/ampmaster low wattage pumps, you really need to maintain the full size plumbing.