Is the overall flow rate through a closed loop with a pump constant? I've always though that if a pump can do a specific amount of work, it doesn't matter if the 'loop' of tubing goes up and down, or what types of turns it takes. I've thought this because if the tubing goes down then up (or vice versa) the force needed to push it upwards would be the same amount of force exerted when it goes downwards. Can anyone confirm this? If I'm wrong, why?