[sourdough]

I use chemicals in the black tank primarily for deodorizing. We dump on the 4th day always unless we are boondocking (rarely). When it's hot or with other circumstances that I have finally decided I don't understand, you can get some smell so I just put the deodorizer in there because. Galley tank is the same. After 3-4 days you can get some smell if you're not careful in heat; we just put the stuff in there to prevent any unwanted "something"; and yes, the tanks are cleaned and "sanitized" regularly.