Is this iron deficiency or something else

What's going on here pls
Is it an iron deficiency or something else

I'm on day 5 after the switch
In 20l pots biobizz light started from clones
600w hps feeding a biobizz bloom and a fish mix

Anyone????

is it only on the top leaves?

Excess K can look like that,but first check pH.

myke said:

is it only on the top leaves?

Click to expand...

Seems to be o. The new growth pH is fine at the moment

It’s not Fe deficiency. My first thought was pH fluctuation but It might be Boron deficiency.