Use C.P like any other cleaning product
If the sump is accessible to scrub, scrub it out with C.P. and a sponge or a brush. If it isn't, turn off the sump pump, put a healthy dose of C.P. down the shower drain and let it stand a while...then turn the pump back on, drain and rinse thoroughly with fresh water. Since your sump will prob'ly remain a bit damp, a good squirt down the drain after each weekend (or once a week if you're a liveaboard) will keep it clean and smelling good and the drain running free...'cuz the enzymes in C.P. "eat" grease, body oils, soap scum, hair etc. Use it in the sink drains too...just a squirt down each one once a week.
