u/DropHaunting

I’m a pretty new grower and have 3 photos and 1 auto in a 3x3 tent. The auto is flowering already and I was planning on letting it finish before I flip the photos, but one of my photos has been turned pretty yellow and I’m not sure why.

It’s OG Kush in 3gal bag of fox farm happy frog and ocean forest soil. i’ve been watering with RO water pH’d to 6.1-6.5 and using cal mag +general hydroponics flora micro and gro every other watering.

I’m using a vivosun 200w light at 75% about 17” away from it. Since the yellowing is throughout the plant I’m not really sure if the light is too close or a nutrient deficiency or possibly overwatering?

Any advice helps