I am using DangerDen 12v pump. double heatercore, round resv, 775 cpu block, my setup is Pump --> Cpu Block --> double heatercore --> resv --> back to pump. The pump doesn't say where is waterout, but it got a arrow pointing out, so i believe it is the outlet. Here is the link of my pump
(
http://www.dangerden.com/images/pumps/12v/d4_lg.jpg ).
I am putting it on the ground, same as the picture. I think the top is the waterout. Correct me if i am wrong . thx