hehe.. But with a few big fans the air inside the case will have no time to heat up anyways, it will always be fresh room-temp air inside the case thus it only takes like 1s to replace all the air inside the case..
And blowing hot air inside the case will cook all components including hoses and waterblock and will rise the temp on every single component in your system..Your pumping something like 300W of heat right into you case! it's like trying to cool a CPU when a blowdryer is trying to heat up the block at the same time
No response to why using a big tank? and pump?
Im not full of shit, i know fhysics and i have experice from several WC systems..