Yellow leaves, changed light schedule

From a fellow grower:

So my plants are 2 weeks old and they seem healthy besides that they are a little purple and 1 or 2 of the leaves are turning completely yellow. I bought 3 blueberry medical. I used some ph water to correct the soils ph. I’m using led 35w bulbs about 8 inches away from the top of my plants. My light cycle is 18-6 but I’m changing it to 24 because they seem to not be growing. All the true leaves have popped and look a normal dark green color. Please help me save my plant.

Do you have a ph meter? What is the ph of your growing medium? The ph of the run off water?
What are you growing in?

Baby plants don’t need fertilizer…does the soil have nutrients pre mixed in?

But what was the PH ?.
Did you feed them any nutrients ?
Does your soil have nutrients in it ?

Can you add a pic ? Please fill out this "Support Ticket " Then we can better help you out…ok
COPY/PASTE: This “Support Ticket” into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA

Strain; Type, Bag seed, or NA

Soil in pots, Hydroponic, or Coco?

System type?

PH of runoff or solution in reservoir?
What is strength of nutrient mix? EC, or TDS

Indoor or Outdoor

Light system, size?

Temps; Day, Night

Humidity; Day, Night

Ventilation system; Yes, No, Size

AC, Humidifier, De-humidifier,

Co2; Yes, No

Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you