Yup...C.P. is not only the best bowl cleaner, it's
also the best sump and drain cleaner on the planet. Raritan C.P. is a bio-enzymatic cleaner that not only destroys odor on contact and leaves the bowl clean with no scrubbing, but the enzymes in it "eat" hair, soap scum, grease etc in drains and sumps. And it's easy to use. Once a week, or when closing up the boat, fill the sump about half full with clean water...put 2-3 oz of C.P down the shower drain. After you've closed all the seacocks, fill the sink drains with clean water, add a couple oz of C.P. When you come back, rinse 'em all out with clean water. That's all you need to do keep drains and sumps clean and sweet smelling. C.P. won't hurt anything, so it doesn't matter how long it sits in drains or sumps.People have asked about using C.P in a bilge. It would work, but you'd need at least a gallon a week to accomplish anything...making C.P. way too expensive to use in bilges.