SOIL Yellowing of the leaves

[Kpeels]

My Leaves started to yellow. I'm thinking that it's light stress but wanted to make sure. This is my first grow and one of my first issues.

[azorahai]

It's definitively not light burn but rather some immobile nutrient deficiency, since it's manifesting first on the newer growth. From the looks of it, it would seem like a zinc deficiency, which is usually a sign of a pH problem (probably too alkaline). Are you measuring your water/nutrient pH? How about the run-off? If you're getting hard water from the tap, you should lower it's pH with a "pH down" solution or just some vinegar, but don't try to eyeball it, it takes a surprisingly low amount of pH down/vinegar to acidify hard water.

[Kpeels]

Thanks for your response. I was allowing someone to learn how to pH and I don't think they did it correctly, should I flush it and add new nutrients?

[azorahai]

You can flush with water or nutes, depending on your schedule, but try to keep it within 6-7 pH (recommended range for soil) and check your run-off if it's too alkaline/acidic.

[Rwise]

I agree it looks like a root zone or PH issue.