First time grower needs help. Nutrient burn ?!

Hello guys,

I need help identifying the problem my plants have.
These are my first plants (autoflower) and are around 21 to 26 days in bloom.
I think they might have nutrient burn from what I found online.

My setup:
60x60x160
100W LED (current distance 40cm, 24/0 the whole time but now down to 20/4 to maybe give them time to “sleep) recommended distance for blooming phase is 25cm but with the current problem I’m not sure if it’s the best idea

Temps are around 21-25°C with 47 to 55 RH

pH while watering was around 6.3 to 6.8. (1,5L per plant, 9 L bags)

I measured the pH of my soil yesterday and it was ~6.5
I water every 2 to 3 days when the top soil is dry and the pots feels light. They get the plagron bloom (5ml/L) and got plagron green sensation (1ml/l ) 3x now) <— might be the problem ?!

Do I need to flush them or do I have a different problem ?

Any help is appreciated!
Thank you

Could be a pk problem try adding more potassium

I did some more research and the brown spots on the leaves look very similar to those of calcium deficiency

Yeah seems they arent getting calmag from your nutrient regimen

I was going to say calmag but p diff is similar to calmag diff I just thought because in flower.

that looks normal for a maturing plant. what type of nutes are you using.
6.8 pH is too high for feed water.
Also new info to me, make sure your water temps are between 62-72 degree Fahrenheit
68 is optimal.