Pink, Sanitize, no drink.
To many things to break if there's a build of air pressure. I don't trust air to get all the water out.
I like to put a bit over a gallon of RV antifreeze in the tanks so that un-drainable water, that's below the drain valves, doesn't freeze thoroughly. Mixing antifreeze in it isn't ideal but it may just slush up instead of freezing. This is for my 2 fresh water tanks, my grey and black tanks.
I also like to use antifreeze to get into the small orifices used in the toilet flush and the faucets. The antifreeze clears out any remaining water that could freeze and break those small parts.
On top of that, you need to fill all the drain traps with antifreeze to push out the water. If that water is left in the drain traps, they'll freeze and crack. Never heard of anyone blowing out their traps.
Antifreeze is cheap so it makes no sense skimping on this.
With antifreeze, you know it's protected and protected correctly.
When it comes to dewinterizing. I use bleach and water to sanitize the fresh water tanks. Thoroughly mix it in the fresh water tanks and flush it out a couple of times. Bleach is cheap also.
🙂We don't drink the water in the camper, but we do brush our teeth with it, as well as washing our bodies, dishes, and utensils with it. I want the camper water clean and safe, especially since the kids are using it!
2019 Ford F150 XLT Sport, CC, 4WD, 145" WB, 3.5L Ecoboost, 10 speed, 3.55 9.75" Locking Axle, Max Tow, 1831# Payload, 10700# Tow Rating, pulling a
2020 Rockwood Premier 2716g, with a 14' box.
Previous 2012 Jayco Jay Flight 26BH.