There's a simple gravity fed design that I use that's cheap and fool proof. I wrote up a description a while back... let me see if I can find it....
You need a glass water bottle... plastic will not work, it's not rigid. You'll need three lengths of rigid air hose, one the length of the depth of the bottle, the other two about two inches long. You'll need two rubber stoppers, one for the bottle and one for the PVC straw, and you'll need a piece of 1/2 inch PVC to act as a straw. Lastly, you'll need two lengths of flexable air hose.
Drill two holes through the bottle's cork and force the two air tubes through them, one reaching the bottom of the jar, the other just reaching the other side of the cork. The one reaching the bottom will be hooked up to a piece of air tubing for siphoning water out of the bottle. The other will be hooked up to the PVC straw. The PVC needs to be corked at one end, and long enough so that the top of the PVC straw is as high as the top of the bottle. Air holes are drilled in the PVC at the level you want the water to be in your return area of your sump.
Start a siphon, and water will be pulled from the bottle into your sump. As it does, if there is water above the air holes, water will be sucked up the pvc straw until it's the same level as water in the bottle. Once air is allowed into the straw, the siphon will automatically resume to replace the water.
There's a picture of the set up in my gallery.