Weissguy, you'll need to put a ball valve in the discharge line NOT going to the sand filter. I also recommend a valve on the inlet of the sand filter to shut off before shutting off your pump to make restating much easier. You've got about 12 pounds of sand that is pushing against the output of you're magnum. The pump I use for the sand filter is a submersible fountain pump I got off ebay. Here is a link to the pump I use---
http://www.rambridge.com/products/irrigat/tuscan/tuscany.html I have a couple extra new ones. The model is 2300, it pumps 583 GPH with a max 9.3 ft Head.
