Re: Anyone familiar with DENATURED ALCOHOL?.
In a clinic put on by Thetford at an RV rally, we were told that adding enough salt to a waste tank to keep it from freezing when cold will do damage to the seals. How quickly will depend upon the amount of salt and how well it is mixed. Denatured alcohol is also not a good choice. Both it and auto antifreeze are pollutants and are not legal to dump into a public sewer system. What should be used for waste tank antifreeze is the regular RV antifreeze.
One question to you? Why would you need antifreeze in your tanks since the waste tanks in all modern motorhomes are in storage bays that are heated by the RV furnace? There should be no need to put any thing in them for antifreeze. I am sure that you have tanks that are in heated bays. If your plumging does not freeze, neither will the waste tanks.