Grow #6: Gorilla Glue #4 pt. 3

Ok so I though the plants recovered, then I changed out the nutrient water for this weeks ratios and 2 of the plants started showing signs of stress again. It looked like the same kind of stress as before, Nitrogen Toxicity. So I removed a gallon and a half of the nutrient rich water and replaced it with regular 6.0 pH'd water. They all are pretty small at weeks only being between 5-6in in height. The root systems aren't where they are suppose to be. The nutrients aren't too high, water pH is fine. I have two 4-port air pumps going for extra oxygenation. I'm starting to think that I didn't clean the clay pebbles correctly and it's leading to these problems. They are up and down in how happy these plants are. I topped the plants and lightly clipped off the bigger leaves through out the week. They are supposed to be switched to flowering next week, but am a little worried about their health. I'd say 2 or 3 out of 4 are doing pretty good. So that's something. At least they went out grow the tents this time!