Tell us more on how you feed and which nutes of Fox Farm.
you mentioned “ just checking ph and it read 7 “ - if you are using a soil probe - that will be unreliable.
Here is a basic approach to Fox Farm Ocean Forest soil ….. it chimes in around 6.3 ( ish ) in ph right from bag - it is also heavily charged with nutes all by itself. So much so , it can power a plant alone. Without extra nutes upfront. It can run most plants for weeks on just water.
Fox Farm nutes are highly concentrated and their feeding schedule is excessive.
The following is my 2 cents -
Top Dress ( add more FFOF ) to top soil - water that in either with straight tap or ph to range of soil ( 6.5 - 6.7 ) to allow for any ph drift issue. You are locking out potassium ( yellow margins / tip burn ) . So suspect your ph out of whack or feed regiment is causing certain elements to be locked out.
By “ recharging “ medium with more medium- keeps shit simple ….. you are just keeping the medium charged as needed as plant exhausts it. Really that simple.
Fox Farm Nute line could also be used but most of the line is worthless…. All you need is 2.
Gro Big for VEG
Tiger Bloom for Bloom
“ Big Bloom “ ( not what you may think its for - does nothing for bloom ) its a mild ORGANIC solution for microbial life in soil ( micronutrients) . And will not carry plant alone.