Help please spots on seedling leaves

[leafy86]

Anyone know what this is (in picture) spot on first true set of leaves. It's on 2 of my 4 babies.
Got a 1000w and a 600w led about 20inch above them. Been advised by a member on here to have them both on as actual draw from both lights is only about 350w. Temp at canopy 24 humidity 70 growing in normal multipurpose compost and perlite 50/50% mix.

 

[Emilya Green]

I think the plant is already telling you that it is getting hungry

 

[leafy86]

I think the plant is already telling you that it is getting hungry

I usually use organic compost for the first few inch but this time went full multipurpose. Thought it was burn if anything. What you recommend giving them, any calmag or just a bit of foliage pro I use?

 

[Emilya Green]

is this a potting soil all purpose mix or just plain compost? How old is this plant?

 

[leafy86]

is this a potting soil all purpose mix or just plain compost? How old is this plant?

It's 50%perlite and 50% standard multipurpose compost. Check out my journal pls il tag u in it there more info there. They 11 days old now.