Here's an even better way

Drill a number of 1/2" holes (many many many) in your Home depot bucket, set your pump with hose attached in the bucket, put 3/4" pea gravel around the pump for weight
Set the bucket on the cover - it should push down a fair amount if you added enough weight to it, turn your pump on.

It should keep debris from entering the bucket/pump.

Of course, you do have to donate 1 complete bucket to the cause of cleaning your cover.