Orange and crispy leaf tips?

So here are my plants, there about 1 month old the strain is kalichakra. This problem started happening about a week ago on a few plants and now it has spread to almost all of them, I can't figure out what it is...

There all planted in FF ocean forest and they've gotten one feeding about 3 days ago of big bloom and cal mag both at 1/4 strength.

There watered with tap water filtered through a brita filter. Water pH is about 6.4.

Any idea of what this could be?

Temps are a steady 74-78. Any help would be great, thanks!

How far away and how powerful is your light. That is definitely some kind of burn. Whether its nute/wind/ or light is a tough call.

There's a small chance it could be some kind of pest too have you checked around the lower leaves of the plants for unwanted guests?

Looks like magnesium deficiency....
Since you are already treating the problem,all you need to do is sit back and relax...
and maybe step up- the dosage of the calmag...

I have a 400w 13" away. I also have an osculating fan on low about a foot away. So do you guys think its burn or magnesium def?

I said what I thought...

If those are Mandella seeds just water, no food for a couple more weeks. Land Raced based genetics are fert sensitive. Go have a look at the growing instructions. Never treat for 1 element defisincy such as mag. Always treat with something like Cal mag. The reason for this is if youm have a N issue the first think to lock up is the mag, so treating for mag will only harm the plant. Nice grow just water for now.

13 in is kinda far for a 400w. Try to get it as close as possible without increasing temps tooo much. I try to keep mine around 8 in. Its open hood also not aircooled.

Alright so I guess I will just water them for now and see what happens?