PH issues-lockout?

[Dbdigger]

Week 5 flower. We started noticing brown spots on the back plant which is now quite yellow. upper leaves closest to the light. Upped our Cal Mag. Hasn’t helped, continued decline. Now starting to see same issue with front plant. Today we did a flush.
Started RO at 6.5 PH, run off was 5.5 and 5.8 ppm’s 896. Continued to flush raising PH to get higher run off. We can not get it up past 6.1. PPM are around 221, PH 6.0 on really bad plant, 6.1 on front. Is this PH lockout? What do we do next?
light intensity is at 80%. These are Durban purple punch
thanks Peeps in advance.....

[bboyfromwayback]

I’m shitty at diagnosing ph or deficiencies tbh, luckily I don’t deal with them much so I don’t have to. With that being said, I’d raise your lights if it was me. The smaller plants in the front and lower leaves look healthy. It’s the tops of your plants fading. Here’s a link for flushing though when you do have ph issues. I never check my runoff, just make sure what’s going in is on point.

https://www.growweedeasy.com/flushing-sick-cannabis

[Dbdigger]

Thank you for your input bboyfromwayback
The lights are all the way to the top of the tent. We have done a progressive light strength, they are currently at 80%.

[bboyfromwayback]

Sometimes less is more. If I run all my ES’s together I won’t go above 75%. Grows big fat tops for a week or two then fries them. One thing I’ve learned growing under LED’s is never go below the hanging height the manufacturer recommends. And under some lights, stay above what they recommend.

[Farmbuck]

Could you tell us if they are autos or photos.

Try this: https://www.growweedeasy.com/marijuana-symptoms for info

[Dbdigger]

They are photos

[dilvish]

4 foot tent...how high is the plant canopy? did you measure that distance? with an TSL 2000 it should be at least 24 inches above the plant canopy...that's what manifolding can help with, assuming the grow is with photoperiod not Auto.
.
Could be a zinc deficiency because of too much water and the roots are getting damaged. try letting them dry out for a few days

[Dbdigger]

Light is 18" away from the highest point of the canopy right now. We can squeeze it up maybe another 1-1/2"

[homegrown]

Run another gallon or two of ph7 or higher and see if you can get the ph to climb over 6.1. Pour it thru as quick as possible..so it flows out the bottom of your pots. Check ph out after first gallon and see if its climbing. It should come up, just may take a ridiculous amount of water. I've had to flush a problem with coco years ago and it took gallons per plant.

[SoOrbudgal]

If they were mine i'd flush with Epsome Salts then allow to dry begin low dose bloom food again. OMG i just love purple punch strain and DP growen them both. Good luck good growing

[Dbdigger]

We were thinking about a epson salt flush. Thanks for your input!