First Grow - Question about height/leaves curling.

hey there, you're right about identifying problems. I see you're doing everything right but the plant is a bit on the "sad looking" side. Sorry to say this, and i know you dont want to hear it but your light schedule is too intense, you need to reduce it a bit. You can tell that the light schedule is sending the plants into overdrive and they need more magnesium you can see slight yellowing between the veins of the leafs. Try spraying it twice a week with 1mL/L calmag to help the plant recover quicker. The downward pointing tips are basically a sign of root problems , but the roots look fantastic, so the only thing i can think of is that the plant is asking you for some help to push out even more roots. In nature a variety of processes assure that roots are constantly being damaged and rejuvenating... in hydro not so much, that's why i suggest you literrally just cut the tips of the roots off with a scizzor (you can cut up to slightly less than 20% of the roots, so dont be scared just cut the very tips off) . this promotes new root growth. Another less scary thing to do is to reduce the Kelp and switch it out for a different and better chelation agent like enzymes or humic acid. These three actually break down the roots as well so it should fix the problem roots causing the downward pointing curl. Hope this helps ! 🚀