Need help with cannabis deficiency

[uniquecreations]

Hey growmies hope you’re doing great

So I have some leaf yellowing on the bottom parts of the plants.

I am growing fully organic using Bio Tabs products and haven’t been correcting my ph during the first few waterings as it says in bio tabs user manual, it is not necessary but I did start on correcting the ph and since then I have been noticing some yellowing on the bottom leaves. Now I am not sure if it’s a magnesium deficiency or something else so I want to hear your 2 cents about it.
I’ll post some photos so you can take a look.

 

[beluga]

How close is the light? Are you watering the entirety of the soil? What are you pHing your water to? Temperature and RH%?

My inclination is light stress. But there could be a couple things at play.

 

[Aqua Man]

Its linda looking like uneven watering to me