I just installed a new sump pump, auto, submersible w 1.5" drain pipe fitting.

The drain pipe rises 8 feet, with a check valve 2 feet from the pump.

To expedite things, a had ANOTHER check-valve screw-in thingy sitting around,
which I screwed into the pump, then connected the 2' of pipe to that.

So, I have Pump cheesy check-valve screw-in thing, screwed directly into the
pump 2 vertical feet of 1.5" pipe industrial-strength check-valve 6
vertical feet of pipe 90-degree elbow Exit.

Is it OK to have the double-check-valve thing going on?

BONUS QUESTION: Upon re-assembly, I found a small felt-like cylinder thing,
like a small paint roller in the bottom of the crock. What could that be?
(Someone else installed the pipe recently, including the industrial-strength
check-valve, but left the sump replacement to me...)

TIA,
Bob