As a 23yr union plumber, I highly recommend a check valve, to keep all the water left in the pipe from draining back in the sump, unless that black thing was a ch3ck valve
As a complete novice with no union 'pedigree' I know that "black thing" is a check valve. If you want a skilled trades 'pro' who is shielded from being fired for incompetence, unionized labor is where you will find it.
