Just because I am curious, I'll probably do a side by side test this weekend. I can make 0 PPM RO and my grocery store carries distilled. I have a Blue Lab Guardian and will do the following tests:
EC and PH of both. Effect of adding 1 drop of PH Down to 1 gallon of each. Effect of adding 2 ml's of a simple Grow fertilizer to one gallon of each. Might be interesting...with no ions in the distilled water, its doubtful the blue lab can even measure electrical conductivity since, with no ions, there is none. Who knows...maybe I'm totally wrong. We'll see