I think you're absolutely right on the the bag causing them to heat up to fast. When I dump more fish in this fall I will use a different method for sure. We've been blessed with some good rains this week. I'm probably 5-6' from full pool so I should have at least 8' of water in it. The water level is finally up to most of the structure i've put in. So hopefully i will be getting some good FHM spawns going. I've stuck a fish trap in it and caught several FHM, a couple crayfish, and a ton of tadpoles.