I use pure glycol. It's red not pink and doesn't make any acid.

I did drain all the water first, Than ran 3 1/2 gallons thru each motor because everyone and there brother has bought up all the R/V antifreeze around here. Exhaust did run pink. I think I am going to have to look harder for it and do it again just for a piece of mind.

if you have the boat out of the water(I know, I have one that stays in) I would run std car antifreeze, thru it, the pink RV stuff has no corrosion fighting abilities..just flush out on hose before taking to launch, would figure most do.