I've had my trailer about a year and am really enjoying it. (It's an 18' 1989 Terry TT) I bought used and have been making sure I am learning all I should. I was wondering if it a good idea to fill some water into the blackwater tank before using it? If so, how much would be prudent? (I haven't had to worry about the blackwater tank filling completely on a trip, so I have begun to be fairly generous in my use of water after using it for a BM.) I'm also curious, is it a good idea to refill the blackwater tank with water after dumping and let it sit for awhile with some tank treatment in it? If so, how long should I let it sit this way?

You should always have about 2 gallons of water sloshing around in your black water tank to help prevent the solidification of.... solids! You never want to have no water in your black tank, EVER!!!

like Frank said, NEVER leave a black tank empty of water after dumping. it's always recommended to add back 2-3 gallons of water after dumping. you also need the water for adding tank additives.

Camping season.......fill toilet bowl full and flush (2 times) after dumping/rinsing black tank. This keeps tank bottom wet so any poop doesn't dry out. Dried poop turns hard as concrete. Also with 2 toilet bowls in tank it is ready for use.Winter/storage season.......drain/rinse tank thoroughly and then add some RV anti-freeze to keep tank bottom and dump valve seals wet. Water OK but anti-freeze eliminates freeze concernsTank additives....Personally don't use them. Can't stand that 'chemical smell'.When tank vents, seals, 'p' traps, AAVs work there is no smell inside rv except for that moment of flushing toilet, which tank chemicals does nothing for.Use them if you want...it's your rv.Has no effect on me

In addition, using a lot of water when you flush will eliminate lots of problems.

Just use a lot of water when flushing. Never have pre-filled and no problems.Once in a while, we do leave the tank maybe a 1/4 full and tow to the next campground before dumping. An hour or two of sloshing around helps break up any solids.

Pre-fill water in blackwater tank? | Good Sam Community

Old-Biscuit
Explorer III
Mar 31, 2015
Camping season.......fill toilet bowl full and flush (2 times) after dumping/rinsing black tank. This keeps tank bottom wet so any poop doesn't dry out. Dried poop turns hard as concrete. Also with 2 toilet bowls in tank it is ready for use.

Winter/storage season.......drain/rinse tank thoroughly and then add some RV anti-freeze to keep tank bottom and dump valve seals wet. Water OK but anti-freeze eliminates freeze concerns

Tank additives....
Personally don't use them. Can't stand that 'chemical smell'.
When tank vents, seals, 'p' traps, AAVs work there is no smell inside rv except for that moment of flushing toilet, which tank chemicals does nothing for.
Use them if you want...it's your rv.
Has no effect on me
bikendan
Explorer
Mar 31, 2015
like Frank said, NEVER leave a black tank empty of water after dumping. it's always recommended to add back 2-3 gallons of water after dumping. you also need the water for adding tank additives.
FrankShore
Explorer
Mar 31, 2015
You should always have about 2 gallons of water sloshing around in your black water tank to help prevent the solidification of.... solids! You never want to have no water in your black tank, EVER!!!

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Pre-fill water in blackwater tank?

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