Gets hot and stalls out

I used water only (summertime in the Northeast). That is what the manufacturer recommends, if I remember correctly.
Really...That would cause me significant concerns here in west Texas in July/August. We do have RO water I could use (the water here is awful) but I'm not sure I'd be comfortable past 50/50 mix. I have been looking at the Stay Frosty product from VP Racing; anyone have any experience with that product?