Big, white spots on leave - Seedling

Appreciate the help, first time grower here:
Set up: 400w HPS light, currently at the weakest setting
Soil is biobizz allmix - probably going to use the lightmix next time at the start

Pictures are from day 8:
Day 1 being when the seedlings sprouted
Have not used any nutrients jet, watered once day 7 with tap water:
I let it stand for 48h to have the clorine evaporate + ph down to ~7 from ~8

Not allowed to post links as a new user (stupid stuff):
Just go to Imgur /a/8ZCVl

I think the white spot might be mineral leftover from misting the plant with tap water!?
I did move the light a bit higher, thinking that it might be lightburn!?

stop misting, bad practice as it increases odds of damping off in seedlings. No need to ph water going on soil, the soil will buffer it. Good luck, couldn't see your pic.

Alright, thank you for the answer.
All you need to do is go to imgur c o m /a/8ZCVl
Sorry not allowed to post links jet...

Throw420Acc said:

Alright, thank you for the answer.
All you need to do is go to imgur c o m /a/8ZCVl
Sorry not allowed to post links jet...

Click to expand...

Make a few more posts about some bullshit or something and you'll get posting rights. I don't really want to put that link in my computer, hope you understand.

Yes, mineralization from the misting, not powdery mildew! Once your stems harden off you can wash it off. Try to keep her dry until then.

Bugeye said:

Yes, mineralization from the misting, not powdery mildew! Once your stems harden off you can wash it off. Try to keep her dry until then.

Click to expand...

Thank you, appreciate the help.
Have a good day!