Phosphorus deficiency maybe?

Running white widow auto flower from ilgm under a hlg 600 at 28 inches off canopy They are in week 8 and been averaging 75 F and 58 RH. Watering around a gallon every day at lights on (18/6) at 6.2 ph and around 450ppm. I’ve tried flushing, letting dry out then reintroducing nutes but still having issues. At runoff I’m getting 5.8 ph in foxfarm ocean forest and around 1800ppm. I was thinking a PH issue since I had a PH meter issue a few weeks back but is now resolved. I believe the plants accidentally got fed around 5.6 ph water twice before I realized I had a PH meter issue. Ive tried upping the input PH to around 7.2 to try to get the runoff PH up without success… I’m open to ideas.

Definitely dont increase the ph way up in Hope’s to get it back in a proper soil range. That’s gonna give you alot more issues in the long run.
If it were me, I’d get some water and only add calcium and magnesium to it. Ph it to 6.5 and run water through it in small increments until your runoff ph is 6.5 coming out. That will also help your ppm build up. Nutrients are acidic so having a pot full of salt is also going to drive the ph down.
And remember, the damaged leaf’s are not going to fix themselves. So pay attention to make sure you stop the issue. And honestly to me it looks to be more of a calcium issue with the rust spots toward the top of the canopy.


Ok…makes sense. I was concerned about upping the intake PH to much myself. I will try this on next watering. Thank you for the assistance.