Turn yellow

Looks just like an iron deficiency. Tap water usually has enough iron in it but maybe not. RO water needs to be mineralized. Check your ph though before making any changes. That’ll cause all sorts of deficiencies. Ensure your light isn’t too close. 360 ppm might be a little on the low side. My tap water comes out out at 300ppm and I bring it up to 450 ppm for first feed and most cannabis friendly nutrients are well balanced. Check your ph!

Hi there! Have you been giving her any nutes yet and how hot is your soil? Maybe she wants more nutes at this point and you can start feeding her some base nutes now. Usually basic soil has nutrients for maybe 2-3 weeks. Did you notice that mutation too? The leaves have no serration at all, cool!