[GuyBFF]

The Danner Mag-Drive Supreme Utility is probably the most commonly used pump available. I have a 1/2" "upgrade" Danger Den Maze 2, 1/2" tubing and a Chevy Chevette heater core with 1/2" barbs. I originally used a Mag-Drive 250, but when my friend became interested in it for his fish tank, I switched to a 350. There was no change in temperature.

In my opinion, a 250 is more than enough for a well flowing system (like the newer Danger Den products, or spiral mazes.. with a heater core style rad), but if your more restricted a larger pump may help push things along. One thing to note however is I have heard from others that in well flowing systems without pelts or additional blocks, they found temps lower with the smaller pump. Ultimately due to the lower wattage transfered as heat from the pump.