I'm thinking about changing the connection set-up too. But, as i was playing around with it, I realized that we're limited by the placement of the in/out connections. For example, a threaded elbow hose barb would be perfect for the input (output from the pump). But, no can do because there's not enough room to rotate the elbow hose barb. Maybe I'll try a close nipple, threaded PVC elbow, then hose barb. For the input TO the pump, I was thinking of close nipple/tee/close nipple/union. Or, close nipple/tee/straight hose barb. This way I wouldn't have to change anything on the eheim pump. This would also change where the pump sits; it would be facing the I/O directly.
This is where experience comes in with design; planning out the type of connection you want before you decide where to put I/O on the reactor.
For hard plumbing, I thought about for the pump input: close nipple/threaded elbow/close nipple/tee/close nipple/threaded elbow/close nipple/union. Whew.. For the pump output, I don't see any advantage to hard plumbing becasue there are some curves and so forth. Why not use hose barbs and PVC reinforced vinyl tubing?
Matt