You are likely going to run into trouble since you have multiple strains PLUS multiple life stages all on the same reservoir. The seedling in back is not ready for any nutrients yet, while the plants that are older will need more.
Also, you look a bit droopy. What is your res temp, and what are you using for fertilizer? Are you checking pH and EC of the reservoir at least a couple times a day? Fresh hydroton tends to raise pH out of range. You want to keep it right at 6.0 +/- a couple points.