Black tank always closed. Gray tank, depends on size and length of stay. I keep my gray open until the last 24 hours or so, then close it for "rinse water" for flushing out the hose after the gray tank.
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TV - 2015 Ram Truck EcoDiesel
TV - 2006 Jeep Liberty Turbo Diesel (Retired to Daily Driver)
TT - 2015 Rockwood Roo 183
Nights Camping --- 2015 - 19 Camped | Winterized -- 2014 -18
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