Indoors LED progressing plant problems

Hi guys,

Getting a little bit desperate here, my babies are slowly dying.

It's day 25th of the grow.
I have 2 species of autos here one is about 50/50 Indica/Satia and the other one mostly Indica (the one with biggest problems).

Here's my setup.
Indoors, in a room with a lot of space
Temperature: 70F/21C
RH: ~60%-70% (I have two detectors they have 10% of a difference in a reading)
Light: 2 LED QB panels (240W) diled down to 150W, hanging at about 20"/50cm
Watering: I watered them like 3-4 times. Last time about a week ago and the dirt still stays wet.
PH: I try to keep it around 6-6.5. Using liquid drops to test PH.
Nutrition: In last watering I've added a tiny bit of bio-fertilizer for grow stage.
Ventilation: No ventilation, sometimes I open the window.
Till about a week ago a was generously sprinkling the leaves in a morning and afternoon. But I have replaced it with humidifier that kicks in when humidity drops below

Main problem can be seen on this photo. Other plants are also kind of stomped. Leaves grow very tiny.
Any help will be appriciated

60%

if it stays wet for a week its not good. do you have drainage holes?

Yes I do

I'm a new Grower just starting and learning myself, so my thoughts may be wrong.

If the medium is staying wet for a week you should consider transplanting into a higher perlite concentration medium. Overwatering can be gradual, and if so your roots are sitting in stagnant water buildup from the past few weeks. The toxicity would rise causing lockout with root death compounding the issue.

Again I'm just starting and educating myself so take this with a grain of salt!

Spraying your plants allows them to drink from the leaves rather than getting moisture from your medium, which is partly why your pots are staying wet. Slack off on the spraying.
Your plants appear short on Mg...Epsom salt will help.
Be sure you have adequate drainage

If you have the ability to raise your temp, get it up to high 70’s low 80’s. LED likes higher temps