i wanted to do this with the blooms because my veg tent has only been fed so many times, but i was curious. the lowest my meter goes for ec is .2, and fresh tap doesn't even register. i mixed up my nutes and they read .6. the plants were really dry so i ran a gallon of plain water through first (3 gal pot) which most of it just ran right out the bottom of the dry soil. the runoff after the plain water read .6, same as the nutes. so then i ran the nutes through. ec went to 1.4, just over double, and this was after running the plain water through. my plants are fine so my conclusion is that this is normal, and i don't really think there is much to be learned from it except for a really vague idea of what might be in the soil. if someone thinks otherwise i'm all ears. or eyes i guess.