Bottom leaves yellowing and dying, top leaves fine

[PeachHazelx]

RDWC, Just did a water change they're sitting at 720 ppm, 5.56 ph, I use advanced nutrients.

Nice set up! My plants have been burning at 300 so I couldn’t imagine using 700 but I’ll definitely do some experimenting and see how much I can push on them

 

[zacuriah]

Nice set up! My plants have been burning at 300 so I couldn’t imagine using 700 but I’ll definitely do some experimenting and see how much I can push on them

My system is fast moving and highly oxygenated water, thats would prob be the difference. I don't have any experience with what ppm should be in coca or soil...