Arounder wroteI noticed that as well - the foam seems to be thicker and less runny using DI water. Plus, when I foam using DI, if it dries due to heat/sun, it's even easier to wipe off than with (my somewhat hard) tap water.I used to use it for rinse-only. I've been using it for everything now. it really foams.
I need to keep my leaf blower in the cart, I keep forgetting to use it during the drying process... probably because I was just excited to see how well my new Gauntlet Towel worked (quite well, indeed!)