Help with floating filter pad

maze

New Member
I need some ideas of how to hold down a mechanical filter pad on an egg crate "shelf" in my sump.
The pad fits okay at first, but after a few days it starts floating around in the sump.
What could I use to weigh it down so it won't float but also won't block a lot of surface flow area either?
Any ideas would be greatly appreciated.
 
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