It's rather amazing how poor quality those pumps are, I've been keeping my C1 cool with one of these little guys http://www.ebay.com/itm/12V-DC-CPU-Cooling-CAR-Brushless-Water-Oil-Pump-Waterproof-Submersible-AP-/121458053302?pt=LH_DefaultDomain_0&hash=item1c4776d0b6
$6, no problems at all.
$6, no problems at all.
Those are water fountain / fish tank pumps which do work, but have half the pushing power and height as the C1 rated pump. They also have no reservoir, unless you have that pump sitting inside a small bucket of coolant or something?
From the specs that one is rated around 1/2 of volume pushed. I would guess it's partially based on ambient temperature. If OP has very cold ambient it will cool the coolant when in the tube, not just in the radiator.
Personally I would not go this route but I know a few through this thread have. You would use anything that holds water and is big enough to put it in as a reservoir. Reservoir's are not really anything special.