Sorry about that, I did not make myself clear, I meant the discharge
side not the suction side. What I tried to say was a check valve on
the discharge pipe but at the base of the pump.

The new Flotec pump I just purchased states, install check valve to
prevent flow backwards through pump after pump shuts off. But it does
not say or diagram exactly where.

It also says, Flotec valve part #xxx is equipped with an air bleed
hole to prevent air locks. If using a valve without air bleed hole,
drill 1/8" hole in discharge pipe just above pump body but below the
check valve.

From that I would assume they mean low in the pit, as it would
otherwise send a stream of water out of the pipe onto the floor when
pumping if the check valve were above the pit?