your soil brand sucks...hypnum peat can vary in PH from 4.0 - 8.0.....

another grower is going through the same thing....hypnum peat
keeps the soil @ 7.6 even after flushing 6 times, the soil PH cannot be corrected, he is now transplanting to better soil

also another pic of the whole plant may help I see several leaves that appear over watered or most likely nitrogen toxicity "the claw"
another reason to complete a runoff test
soil runoff PH test.......
with PH corrected water (6.5-6.8PH ) pour enough water in the pots so the water runs out the bottom of the pot ...collect & test the PH of this runoff water....