[sourdough]

Dump the black tank...5 gal. bucket or whatever. If you live in NY you don't need to be putting "a few gallons" of water in any of the tanks for winter. You also don't need to worry about "smelling" come spring if you don't. Putting water and a packet in the black tank going in for winter is a recipe, to me, for a big problem come spring.

Dump the tanks for winter. Add some anti freeze to them to protect them; no
"few gallons of water" or packets of anything. Make sure you have dumped and flushed the black tank. The last filling of the black tank should have had deodorant etc. in it. We've done that for years and never had a
"smell" of any kind - just clean it out when you dump.