New Sump Pump question

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
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I personally would not use 2 check valves.
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