Yellowing and warped leaves

Hi all! Can anyone help me with diagnosing the yellowing on my plant?

Plant info: It is an indoor auto-seed, and I keep the light constantly on. It has been three and a half weeks since I potted it. Two days ago I noticed the yellowing and tried to change the water - switched to a lower pH level. But it doesn't appear to have made much difference, though it does continue to grow.

What are you feeding it with? At 3.5 weeks, you're not gonna get much off that. Maybe a few grams if you even make it through flower.