Deficiency or ph?

Having a few problems and not sure what it could be. I use plant magic soil with plants magic nutes
So my plants are great through veg proper nice colour and healthy and then are also still healthy for the first few weeks or so of flower but then all the leaves start to Yellow off you can see in the pictures majority are ok but the odd leaves are starting to turn any idea what this could be? The last pic are 7 weeks into flower you can see all the leaves have turned and this started weeks ago

Back off the nutes a bit. Some of that dying off is normal at the end of thier life cycle.

DoubleAtotheRON said:

Back off the nutes a bit. Some of that dying off is normal at the end of thier life cycle.

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I have done what do you think of the younger plants any idea why them leaves are turning ?

Mid leaf death in veg is usually a Potassium deficiency.

If you have a PH swing, you'll see it in your new growth. Just up the K a bit. You won't see those recover, but just pluck them off after upping the K and wait...and by wait, I mean like 10 days. Then observe.

I had some plants in veg that had similar mid/lower leaves and the culprit was I failed to add Epsom Salts (Magnesium Sulfate) to the Jacks base nutrient in coco. So either it was a sulfur or magnesium deficiency. I started adding around 1/4 teaspoon per/gal and the plants bounced back within 24 hours.

The pics are kinda scattered as far as when you've took them so I don't know if we're looking at just 1 issue here.

When in doubt feed an input of 6.0 PH for me. (Yellow color with drip tester)