We use a check valve in our small 500 GPH pump which is our primary. We do not use it as a anti-siphon since that is separate. We find that this lessens the water that feeds back down the hose and into the bilge after the pump completes its cycle.
We do however have a secondary 3700 GPH pump that does not have a check valve.
Originally Posted by CLucas
Check valves generally get a thumbs down when it comes to bilge pumps, since they can easily render the pump useless if they get clogged or fail to operate. Too close to the pump on a long hose run from bilge to thru-hull and the pump may not have enough pressure to open the check valve, rendering it useless. There are plenty of articles available on this topic -- from Cruising World:
Here's the article: Wire and Plumb Your Bilge Pump Properly | Cruising World
. There's lots of good advice in these forums as well.