i agree for my last res change in five gallons I came up high with ppms. Actually first I was low then I was way high. I will try your system tomorow when I res change. I never had one prob and better growth tho than I ever had so far this last veg period. Not one burn I thot i was invincible for a while. Now I am on top of my one prob, keeping the buckets filled. Lol, top offs are annoying. But now I got a garden hose in my grow room and I just turn her on! Cake.
But seriously the calcualtor is a cool thing still, even it was a little off. I still swear by it basically. I do however advise two weeks of transistion for a sativa or long flowering indica as the extra nitrogen is needed later.