[arcsylver]

Another option I have considered is multiple pumps.

Using Hydor L30's one per cooling loop that each return to the top of the radiator via thier own separate cooling loop and then pass through the radiator to the single outlet at the bottm this should create enough cooling to keep multiple computers nice and cool.

It should also not hinder the pumps since they would not really be fighting each other except at the radiator and gravity would lessen this effect since the radiator is a paralell pass design I could have three cooling loops easily with more a simple hole and tap away by adding another 1/2" barb connection to the radiator.