Bottom leaves normal top not

Is this light bleaching or cal mag deficiency? Bottom leaves are normal but top aren’t

Hard to tell with such limited info but generally when the tops are affected like that something is causing micronutrients to be locked out or there is a lack of them in the medium so the plant can't get them.

If it's a lockout then high pH is the most likely suspect as most micros are not mobile so the plant can't steal them from the older leaves to keep the tops healthy and growing.

So what is in the pots and what do you water them with? Added nutes?