I used an old IO salt bucket for my fuge. I drilled a hole in it with a hole saw, used a Uniseal bulkhead fitting and have it gravity feed back into the sump. The nice thing is the bucket is taller than the sump so it makes it easy for the return and I don't have to have the bucket sitting on anything. It works great, except my original idea of using some netting to act as a screen on the overflow. Don't do that, bad juju. (It clogged and overflowed then my ATO kicked in and dumped 30-40 gallons FW into the tank during the stir cycle on my Kalk reactor.)