HELP! Leaves are turning brown, dying plant

[herbgrower]

yeah i repotted it in fresh soil. fingers crossed

 

[herbgrower]

Tersky I am betting on that.

 

[herbgrower]

Hey guys some bad news. The seedling is showing no recovery instead this morning I saw its newest of leaves getting tip burn and turning brown. What should I do? Should I repot it again only with coco and perlite? Do you think this is nitrogen toxicity?

 

[herbgrower]

This is the latest condition. Interestingly the newest leaves which tip started turning brown today is now curling upwards. I think this is due to mismanagement of pH which led to nitrogen toxicity burdened with over-watering probably.

 

[herbgrower]

Hey guys quick update! As you know my seedling was sick due to pH and other load of stuff. I ordered the pH tester but it hasnt been delivered yet. The medium was drying out and I had to improvise. I had soil pH tester. I took the coco-perlite mix with which I potted the seedling. Tested its pH, it was 7.5+. I mixed water with local pH down liquid, watered the soil, tested pH after hour and it was near 5.5 later dropped to 6. I gave the same water to the sick seedling. After an hour-two the pH was set to 6-6.5.
Today I noticed that pH level was going up to 7 after 24 hrs of watering. The moist meter reading was half meaning half of the waster was drained/used. Something caught my eye was the latest leaf which recently turned brown, today it further turned white-ish. I tried to capture it but because of flash and the object being white, it is just a white flash on photo. I have marked it but it is still not noticeable. It is not powder, this is the leaf turning white.
Can you guys tell what it is? I am just learning from the nobbie mistakes but I still want to save this plant.

 

[Tersky]

how far are the lights. Sounds like light bleaching/burn
https://www.growweedeasy.com/cannabis-plant-problems/light-burn

 

[herbgrower]

Tersky The light is very close to the seedling because it is only 25W actual power draw right now. It also has more red as compare to blue and white. Do you think I should move the light?
Edit: There is no cupping or clawing. Only the tips turning downwards which is consistent symptom since the problem started. I am trying to pay very close attention to heat and light stress although I am just noobie. Your insight would be very helpful.

 

[Tersky]

It depends, how close is very close? Usually the manufacture has a distance to canopy recommendation. LED's are notorious for light burn and are supposed to be kept far away in comparison to cfl. https://www.growweedeasy.com/led-grow-lights-burn-cannabis-buds
Also i wouldnt grow seedling with red light as red light makes it stretch.

 

[herbgrower]

Tersky I moved light to about 6 inches from the seedling. This is just some cheap 25W makeshift light so I am afraid that the seedling wouldn't get enough intensity if move further. The manufacturer has like no say in this. They don't understand me when I ask for data. They think light is not working and asking me if I want replacement. Lamo I am waiting for PAR600 which should be landing in week. I can go methodical after that.
On that note do you think this is because of pH fluctuations?

P.S. : I started talking to my plants and apologized for my carelessness