Dishwasher pods and Black Tank leftovers

Hey All,

Have any of you ever tried dishwasher pods/powder in the black tank to get rid of stubborn "leftovers". We use plenty of water in our black tank and have the built in black tank flushing system yet still have stubborn sludge. Since it works great on baked on stuff, I was thinking about filling the tank half full with water, dropping in a couple pods and letting it slosh around while driving.

Has anyone tried this?

Thanks!