My fuge is separate from my sump, and it sits at a higher level, so the water is gravity drained into the sump, then the sump water gets pushed to the tank by two return pumps.
I don't think they'll survive the journey all the way to the tank this way, that's why I tried to take some myself and dump it in the tank at night, when fish are sleeping.
I think Pettee86's idea is great. I'll give that a try.