My pH has been between 5.7 and 6.0 the entire grow, except for the first week or so after I got my meter and didn't calibrate it! The nutrients for my first two weeks of flowering were only 50% strength and the res was a couple days shy of 2 weeks old when the yellowing started which is why I thought maybe they had used up all the nitrogen. I did a res change yesterday (on the 2 week mark) and added full strength nutes since I am entering the 3rd week of flower. My PPM is at 1800, which seems high, but I did a search on Google for average PPM levels and found a couple different sources that says you can have your PPM that high in flower. The Pure Blend Pro jug suggested 675 mL for "Aggressive Fruiting/Flowering" so I added 500 mL. The veins of the yellow leaves look like they are turning green; do they normally turn green again or do they just die out? I'm halfway to the promised land and I don't need things fucking up now!