First time coco, side-grow #2

This is my side-grow number 2. I do have 2 girls in flower, but I wanted to fill my room, and I started these a week after my first side-grow, as I was thinking this lamp and tent will nicely fit 6 autoflowers. This is my first time (Well second, counting the flowering girls) growing in coco, and I still not all sure what I do, but I will try my best to do right, and learn from this. I am using RO water. The girls are on day 16, and everything seems to go good. I took the pictures right before watering them as they looked kinda dry. I see they are dark green and are going to lay down on the nutrients on the next feed. The girls have been topped around day 12, and LST was done on the same day Day 20: I see some dark green leaves and I'm sure I have a Nitrogen toxicity. I think I mad a bum-bum, giving my babies the nutrient water for my grown-ups 😱, so I have given them a good flush with ph 6.0~ RO water, and let them dry out, before giving them a light-mix, and hopefully this will do the trick as they are still growing strong 💪