Correct - three tanks. Fresh, Grey and Black.
Always put a gallon or so of water into the black tank, otherwise solid waste tends to clump and harden. You should also be putting a bio agent in the black tank to manage odor and help disintegration process. ( be sure to use RV or septic friendly TP as well)
Keep both Grey and Black tanks closed until full or ready to dump.
Dump black tank first. Dump Grey tank to flush black tank debris down the drain hose.
So long as you’re not worried about freeze, put another gallon or so of fresh water back into both grey and black tanks and add a bio agent. You don't have to add bio to the grey tank, but it will help manage odor.
Jim & Kim from Colorado
2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
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