Normal fade? Or problems

Hi there. First autoflower run growing Gelato Auto by fast buds. Is the yellow and clawing on the leaf circle typical of a plant this age? (Close to 40 days) or do I have something else on my hands? Using biobizz light mix with biobizz nutes. My old cheap PH pen just bit the dust so upgrading that literally today.

So do u need to pH in that soil

Looks like some pH issues or Calmag.
Not familiar with the soil or nutes yer using