That's a good thing...means your plant is sucking in some N among some other nutrients. 24hrs within a res change my pH always goes up by about 0.5, and did this time as well, but I am just now discovering that one of my bucket's lines is clogged. I checked pH and ppm on another bucket, although the pH was still 5.6 vs the normal 5.8, everything was normal and water was recirculating. In the other bucket, the one whose line isn't pushing out any water, the pH and ppm's are way off and I'm guessing it's where it's not recieving the pH up that I applied to the heart. Soooo, now I gotta figure out how to unclog a single line in my RDWC without having to pull the line out of the netpot, for I ran my water line down into it, and if I pulled it out it'd be ripping roots....am I making any sense? Haha sorry man, my mind's a bit hazey right now.