Hello…lil’ help please

[Inked]

Hello, friendly neighborhood farmers! I’m working my way through my first grow and everything has gone very well so far. A few days ago I noticed these brown spots forming my my leaves. Some were really bad and I’ve been trimming like crazy. It seems to have slowed down but I’d like to know what you all think the problem was. I’m leaning towards nutri burn but would gladly read your thoughts.
Thanks for any advice or input.

 

[Ems49]

What nutrients and medium please.

 

[Ems49]

Maybe starving for calmag, whats your feeding schedule

 

[Inked]

What nutrients and medium please.

Thanks for replying. Here’s what I’ve been using/doing in a soil medium

 

[Inked]

I am in week 11 and these are auto flower if that makes a difference

 

[Inked]

Maybe starving for calmag, whats your feeding schedule

After researching further, I do believe this is the problem. I’ve been watering a little low on the PH at about 6.1 - 6.2 causing calcium lock.
Thanks!