discoloured leaves

Hi guys; 2 weeks since flip, and some (not many) of the new shoots look like this:

What’s wrong with my girl?

BTW most of the leaves are 5 fingered.

What kind of setup? pH? Looks like the beginnings of a pH problem.

400w hps in soil; to be honest, I’m not too scientific about ph; always try to be btw 5,5 - 7.

Got one of those 2 drops in a plastic tube things.
Not sure how accurate they are

Is it worth investing in a digital ph tester?

Never had this problem before when growing outdoors