Sounds neat if you could set it on a temp sensor in place of a water level determining when it move water.
a bilge pump is for large amounts of water seems like it would be a bit much unless you run 2" tubing
^You'd want water moving constantly while the system is on. You really don't want water sitting on a video card getting hot, while 3" away, the water in the tubing is cool. You can get hot temps in a cooling loop if you don't have any circulation...trust me...I had one of the older MCP350's that wouldn't start up at boot (on occaision...Google it) and my GPU temp would start to climb through the roof. If I bumped the pump, it would kick on and the GPU temp would plummet in a couple of seconds.