Main drain shut off valve question

[kingbud]

I don't know where exactly in the system this valve is located -- possibly a shutoff before the pump to isolate that line from the other suction? (well Duh!! you said it was a shutoff valve...) -- but this I know for sure: Gate valves are the reason God created ball valves. Definitely go with a ball valve, preferably PVC, and also one that comes apart on one end so you can get at the seats if you need to.