I'll refer you to the manufacturer on that. I wrote those words, and after researching it seems I definitely mis-spoke when I chose the word "incompatible." I made an incorrect assumption. It seems other coolants and water ARE INDEED compatible with their coolant.

I found this quote on the Evans website:
"Evans Coolant is a patented blend of chemicals, most of which are commonly found in conventional anti-freeze formulas, and additives with no water. It is not a gel and will not turn gooey if anti-freeze is added to it. If something were to happen on the trail and you are forced to add water or anti-freeze, it will simply perform like conventional anti-freeze, no worse."

Sorry I chose bad wording there. I'm just attempting to summarize info I've read from a source I very much trust...and it seems I did so poorly. Just to be clear, I haven't used this product yet, and I may not. So I have no first-hand experience or knowledge to share.