I just got a new sump pump for my septic tank. One plumber put the wrong pump in, and I had to hire another plumber to put the right one in. He recommended (after he installed it) to put a paver underneath the pump. I can see a lot of sediment buildup and it's pumping even that up to the leach field. This is a seven foot deep tank, and the paver would likely be there underwater for years.

What kind of paver do I need? Do I need to seal it somehow? Not sure how I would get it down there