do keep me posted im eager to see resolution, I feel invested :P

oh my...

This could be it. I'm using exactly Evo stick adhesive for the mylar lining.

Time to white spirit this bitch I have high hopes again

Good job dood!!!!! I think you got it!!

How much water at a time are you giving it? and how often?

And yes you have to much light. Do you have an android? Are you using blurple lights?

Guys quick update - issue resolved!

Culprit: Evo stick adhesive

Resolution: white spirit the insides of the case, cleaned it with iso propyl + boiling hot water, I used generic PVA glue to line the case with thick board to block light leak, used duct tape to eliminate light leak completely, and used rustoleum white matte spray paint instead, let it dry for 72 hours with exhaust fan running max speed and a heater inside to dry/cure quicker

Plants have been in the case for 48 hours now, no drooping, visible growth and no dodgy colours n shit.

Also moved over to chemical pH strips, thanks for all the help!

Avoid Evo stick adhesive, will definitely make your plants trip!