Brown spots please help

So I'm 2 weeks into from seed and one of my girls is developing brown spots. I'm not sure what it is. Its only on 4 leaves at the bottom. And the soil is new so I'm ruling out cal-mag issue. Any ideas?

what soil? i get this happening some times, only on the lowest leaves, iput it down to it getting used to the soil.
ive found a seaweed watering b 4 i plant it up in new soil stops it for some reason.

I'm using a happyfrog/strawberry fields/perlite. With diatomaceous earth and dolomite lime

The problem Is getting worse on this girl and starting on another lady. I watered with calmag today. I just don't understand... the soil is BRAND NEW, I thought you don't need calmag for awhile at first? Can someone please explain this to me. Or is it wind burn? I've had problems on grows but never this early on. They are at 2.5 weeks from seed. And now that I think about it.. I switched from tap water to distilled recently.

Tokeybear12 said:

watered with calmag today. I swtched from tap water to distilled recently.

Click to expand...

Calcium def. Use tap water instead of distilled.

I thought calcium dif started at the top?

Could it be some root stress, those fabric pots can let the soil shift and tear some roots.

Calmag seems to have fixed it for me. Somebody mentioned that ph problems could be causing lockout too.

It was indeed a calmag issue. As you can see in this next photo, everything seems to be doing very well