Leaves problem or?

[k3yv4n]

Hello
This is my first plant growth
My plant is 90 days old
It's LSD25 auto
The old leaves of my plant are not normal and are deformed and some shiny
The leaves around me turn yellow and the leaves die and this problem is growing
my ph 6.5
my temp 24 -28c
in soil with poland npk 20 20 20

nutrition for first and after advanced i used .
and my light is 1800 watt led and Cob fullspectrum
i have 6 plant


I have 6 plants
And 5 have this problem with their old leaves and new buds with yellow leaves
Where is my problem
No problem with soil washing, no fertilizer or fertilizer reduction and this problem has worsened within 1 month
I'm right before flowering
Is it a disease or a fungus root?
Do I need to do something to fix this problem?

 

[Mayne]

Overwatered, Not enough calMag, cooper deficiency, most likely wrong PH, get your PH up around 6.8

you should be watering when the pot is very light, like %20 left in water weight.

can u take a pic of the entire plant?

 

[k3yv4n]

Overwatered, Not enough calMag, cooper deficiency, most likely wrong PH, get your PH up around 6.8

you should be watering when the pot is very light, like %20 left in water weight.

can u take a pic of the entire plant?

tnx for replay
i watering every 3 - 4 days when pot is very light !
after washing my soil by 5 litr water at 6.8ph in every pot the new leaves is good . but the older is like that .

the color of new leaves are light green ....