Quick Connects are fittings that can be pulled apart easily, similar to the kind used on air hoses for pneumatic tools, but for liquids. There are many types but the old standby is the
Koolance QD3 Series. I think Remayz may have been thinking that you had a set of Quick Connect fittings that were not fully pushed together and locked. They are designed to snap shut when you pull them apart so coolant does not get out. Quick Connects are also restrictive and will lower the flow rate a bit. It is possible that the rotor inside the High Flow Next is stuck or damaged.. You could try tapping lightly on the side of the housing and see it will start spinning. Its also possible that a piece of foreign matter from somewhere in the loop got sucked into the High Flow Next and is preventing the rotor from spinning. This is unlikely. It may also just be defective, which is quite uncommon but not impossible.