Bong better than radiator? Yes but with a radiator you have no way of reaching below ambient water temps. BUT you dont have to worry about refilling your system.
Here is what I would do:
Make a 4'-6' vortex tube and use that large pump of yours to power it. Then have a heat exchanger that will isolate the tap water loop (used for vortex) from the distilled water loop (for cooling CPUs). Use a Sedra 500A or better pump on the CPU loop and use 3/8" tubing to all the machines. That should provide CPU temps 10-15 degrees of ambient (depending on the CPUs you are cooling)
The vortex cooler would also look cooler
