Question What should my runoff ph be mid flowering stage?

[Time Traveler]

I need some insight, I’m growing GDP and GSC photoperiod seeds in coco, compost, Bio-char, perlite medium. I used organics during veg stage, GH Flora series added at transition stage. I’m in beginning of week 6 flowering stage. I noticed plants wasn’t growing so I checked the ppm and ph off my runoff. My ppm was higher than ppm going in, my ph was 7+. When I feed my nutrient ph is a 6.0. So I flushed with nutrient water phd to 4.0, 2 gal through 5 gallon pot check ph runoff still 7. Flushed more nutrient water 2 more gallons phd to 3.0 (red) using testing solution, checked ph 6.5 sweet pea green now. 2 more gallons and still greenish 6.2ish. What could be the catalyst? The organics I used were humus based compost with bio-char and mycorrhizae blended in Medium. Prepped medium with spirulina powder, stingy nettle root and leaf powder, dried kelp, sea moss water, molasses & agave nectar watered in during seedling stage to be ready at veg stage. I simply watered during entire veg + cal-mag, started using GH Flora trio with beastie blooms, super thrive, kelp, molasses, green coconut water & agave nectar during flowering stage. Ph is always 6.0 highlighter yellow (using testing solution). I have read a 7 is good range for soil and I am using the coco coir like soil with the organics, so why are my girls struggling at this ph range? Both plants are at start of week 6 flowering stage. I don’t want to go into panic mode and do something to create another problem while correcting the first issue. Some friendly insight would be much appreciated. First 3 pics are the same plant last pic is different plant, both Girl scout cookies same age, nutrients & lighting etc.

 

[Reznfingeez]

They look healthy to me

 

[Time Traveler]

I discovered they had nutrient lockout after some reading. They weren’t growing, I couldn’t see any visible signs of deficiency other than the dark green leaves and with no downward bending tips I didn’t suspect nitrogen toxicity. I ran phd 5.5 water through them and my ph run off was 7+ blue green using the testing solution, my ppm was 2889 in one and 3462 in another. My medium is coco/perlite/biochar/Mycorrhizae. I ran organics during veg so my medium is like soil. I switched to GH Flora series at switch to flowering stage. I think the microbes was buffering a lot of the over feed, I use fish waste water also sometimes as feed alone. After flushing with 15 gallons of 3.0 & 4.0 water ph dropped to 6.4 no lower, ppm 780ish But after the plants started growing fast.

 

[elite_hemp]

It's good that you're monitoring pH closely. However, pH fluctuations can sometimes stress plants. Going from a pH of 4.0 to 3.0 during flushing can be quite extreme and might cause additional stress to your plants. Generally, a pH of 6.0 to 6.5 is appropriate for coco coir and soil-like mediums.

 

[Time Traveler]

It's good that you're monitoring pH closely. However, pH fluctuations can sometimes stress plants. Going from a pH of 4.0 to 3.0 during flushing can be quite extreme and might cause additional stress to your plants. Generally, a pH of 6.0 to 6.5 is appropriate for coco coir and soil-like mediums.

I agree but the only way I was able to drop my of ph 7+ was to run low phd water through the medium a few times. I definitely stressed them then, heat and light stressed also, she developed a few foxtails this week.