Possible yellowing happening

I’m growing gorilla glue autoflower from ILGM and I’m using fox farm ocean soil. They are about 3 weeks old and up until now they were doing great, maybe they still are. It looks like 1 out of 5 plants are turning yellow ever so slightly and the very tips were yellow but not much of it. I haven’t added any nutrients at all yet and I watered the plants last night after6 days with water at 6.2 ph. I’m at about 55% humidity and 73ish for temperature. I’ve got good ventilation in my grow tent. Here is a couple pictures… Thanks

Welcome and they look good to me fill out a support ticket it will help if you have problems in the future