Peggy is right about “CP” (Clean Potties). I used to open up my shower sumps and clean them regularly. It was an aweful job.
Then I read about CP. I squirt a bit down the shower drain when I leave the boat every couple of weeks. The sump never stinks and that one more maintenance item I don’t have to deal with now. I haven’t opened up my sump for 2 years now!
Additionally, I used to clean the sump with products that contained bleach. Invariably, the the float switch would fail shortly after that. Then I had to replace that darn thing.
The CP solution is one that I’d recommend to everyone 👍