I'm scared to death of plumbing a sump into my reef. Can anyone point to some places that are good guides to basic plumbing do's and don'ts and stuff like that?
Make square cuts and deburr
Prime joints
twits joints while making them up 1/4-1/2 turn is good
Isolate equipment with ball valves and unions so they can be serviced. For example you return pump should be sump-valve-union-pump-union-valve
Kepp the number of elbows to a minimum
On the suction side of the pump it would not hurt to use one size bigger pipe and reduce at the pump. Not a hard rule, but somthing I do.
Drill an anti-syphon hole on the return line right at the water surface. Make it 3/16 to 1/4 in diameter. This will keep you tank from being sucked in to the sump during a power failure.
At the top of this page is a link that says "Pump Selection Guide". When you click on this link, it'll take you to a page that has a very detailed article on pumps and plumbing along with a HUGE list of common pumps used in the aquarium hobby along with a link to a page that will help you optimize your plumbing.