SEEDLINGS DYING PLEASE HELP

My seedlings are dying and I dont know what is causing them to die.
I water with ph 6.5 to 7
Plants are under a 456 watt led
I thought it was nutrient deficiency so i added 1/4 of flora series nutes. dont seem to be helping.
I also thought it was gnats infested so I also watered with neem oil.
I dont know whats going on, they are currently on week 3 and are dying slowly.
Do i need to up the nutes or are they burning
germinated in vermisoil. Never transplanted. 3 gallon pots.
Heat ranges from 76 to 81
Humidity is always aroun 49 or 50%
they are also autoflowers skunk1
Someone help!!! first time grower!

If you want to check the nutrient level collect some of the run off water next time you water and measure it with a ppm pen. That's what I'd do. Check the ph as well.

I would hold off on the nutes for now, how often do you water

I'm going to check the ppm today when I water it. I water once every 4 days or so. Idk if I should flush it or just let it be.

Ok so I just did the ppm test and it was 158x 10. That's why they are burning. Do I flush with regular ph water or nutes adjusted to the right ppm??

Imo the ph should be kept closer to 6.3 ish & not 7, someone correct me if I'm wrong. Good luck..

What type of soil. It. Looks like nute burn to me.

I don't know that anything is wrong. Those leaves that are browning are throw away leaves, they don't matter. If you are getting clawing on your upper leaves then it is overfed. Otherwise just let it go on water only for a bit.

as far as feeding and watering, get a ppm reading of your water. Then add the ppm reading after you add nutes to you water. I would kep it low like 300 ppms of feed. they are still small and they don't need much feed. Once the small circular leaves at the bottom of your plant are yellowing then its time to feed them. The small round leaves at the bottom feed the plant through its baby stages. If you do feed thgem make sure you food PPMs are no more than 300 for now not including your water PPMs. So do some math my friend. If you feel you over fed them then quickly flush them with 3 times your pot or soil size. Example: 5 gallon pot needs 15 gallons of plain water (preferably distilled for a flush).

alright. i did a complete flush on all the ladies. we shall see how they go!