Unidentified illness

[MadBuds]

I've got a problem with these spots appearing on my plants, the older leaves tend to cop it first.
They were grown from bag seed.
I had a problem with whitefly but that seems to be under control.
Not sure if its fungal, a pest problem or a nute deficiency, seems to be killing one strain in particular, entire branches are slowly dying off.
Please help

 

[canabinerd]

A picture is worth a thousand words.

 

[canabinerd]

You can look here and compare your problem to the pictures https://https//www.420magazine.com/...is-plant-pest-problem-solver-pictorial.81266/

 

[Mono]

Like said above. We need pics to be able to help.

 

[goathead]

nute lockout maybe,maybe fungal