The first time we winterized the RV I listened to the instructions of a friend…”Just put RV Antifreeze in the holding tank and run the pump till all faucets have it”.. sounded simple enough
I wish I would have had a clue about what I was doing and saved myself alot of time in the spring. Instead of draining the antifreeze back into the bottles and then rinsing the tank first I filled the water-tank and started flushing the system which of course took forever and required multiple tank refills and breaks for the water-pump to rest. We probably spent 4 hrs of filling, flushing and draining tanks before we had clean untainted water.
Ever since that day we decided to winterize with pressurized air which takes maybe 15 minutes total and de-winterizing is a non event since all you do is start using the water.