2 loops
1) 3/8" tubing. DD CPX-pro pump, HW labs Black Ice stealth 240 X-flow radiator, Crossfired 4850's with Koolance
vid-485 waterblocks, Swiftech micro res, back to pump.
2) 1/2" tubing. Lang D5 vario pump, Fesser X-changer 120.3 radiator, Core2Duo E8400 CPU, Home made reservoir, back to pump.
The GPU loop is internal to the case with the radiator mounted on the back, the CPU loop routes out the back and down into the case stand/cooling box.
Nether reservoir is the highest point, I move the radiators around and re-mount them to clear air bubbles. I don't think any air is trapped in the water blocks they are the geatest point of restriction and any bubbles should be pushed through by the water pressure. Once a bubble is traveling through the tubing the reservoir need only have some depth and the intake well above the outflow, then any bubbles that entire the reservoir float up and collect in the top while the heavier fluid drops and collects at the bottom to return to the loop. Flat single bay reservoirs are to shallow to do this and any reservoir will start to suck air back into the loop if the fluid gets to low.
As far as bubbles just staying in the loop, they might if the flow was weak. I could see the Lang D5 on its LOWEST setting maybe allowing bubbles to stay in the waterblocks but the pressure from it on high would be enough to push them through, or so I thought... I will look into this but I think its a question I already pondered and discarded as not an issue with a decent pump.
Will
post some pics of the internal setup in a bit.