Gray water tank anti-freeze

[LoveToCamp]

Guess I'll start this. Hate to see a forum with no threads.

I camped a November weekend in 2012, where it got to 9° the second night. Didn't warm up much by the time we were ready to leave in early-afternoon. I tried to drain my gray water, but the slide blade was frozen in-place. Had to have it exposed to the sun for over an hour before I could empty it.

Discussed the situation with some folks, and it was suggested I put some salt in the tank. This year, same November weekend, I dissolved about ¼-cup of salt in about a cup of hot water, then poured it down the sink drain.

Didn't get nearly as cold this year, so I don't have a clue if it would have been enough salt for 10° or colder. Had no problems this year.

It was my 2012 2417, so I only had 8 gallons of effective gray tank capacity. Most TM units have larger gray tanks, so more salt is likely in order on the rest of the lineup.

[MisterP]

Another option is to take the slide apart occasionally and lubricate it with some silicone grease.

[Pele2048]

They sell flat silicone rubber heaters for heating up oil pans of engines used in cold climates:

https://www.amazon.com/Kats-24150-Watt-Universal-Heater/dp/B000I8TQD6

I've even seen larger ones for troughs in farming supply stores.

Just slap one of those bad boys on the bottom of your tank with some double sticky sided tape and call it a day.

[commodor47]

Another option, assuming you have full hookups, is to use a hair dryer to free up the slide valve. Most power posts have a separate 120 volt outlet making it fairly easy to use a hair dryer. Ask me how I know this works . . .

Dick

[dcrogers]

A word of caution about using flat silicone rubber heaters that are built for heating engine oil pans in cold climates. They can get hot enough to deform and melt the plastic grey water tank. One user comments on Amazon page says, "The pad gets really hot but its OK on metal surfaces. Keep it away from plastics."

Another thought - instead of salt, how about adding some automotive antifreeze to the grey water tank? Maybe also the toilet tank. The TM manual says (winterizing): "Antifreeze may be added to the sink and tub drains to keep the drains in working condition, but freezing will not damage the traps." The amount of salt or antifreeze to add depends on expected minimum temperature and the amount of grey water. For example, the freezing point is 10°F for a solution of 75% water and 25% antifreeze. And for any such additive, there may be environmental concerns about dumping the tank.

[Tymanthius]

For example, the freezing point is 10°F for a solution of 75% water and 25% antifreeze. And for any such additive, there may be environmental concerns about dumping the tank.

They do make pet/environmentally safe antifreeze, FYI, as well as RV specific stuff.

[Bill]

Another thought - instead of salt, how about adding some automotive antifreeze to the grey water tank?It is illegal to dump automotive antifreeze down a drain in many municipalities. It mucks up the sewage treatment plant somehow. I can imagine that in a campground with its own treatment plant, you would be even less popular. As you noted, there are environmental concerns. The TM manual says (winterizing) ; "Antifreeze may be added to the sink and tub drains to keep the drains in working condition ..."I'm pretty sure they meant non-toxic RV antifreeze.

Bill