What's your water temp and tell us more about co2 ?

CO2 should be used at a temp of around 90 degrees to work well. It must fill the room to about 1500 and then the whole room flushed with fresh air every 4 hours. Then repeat.

When doing hydro the biggest problem is keeping your water temps down to near 70 degrees.

To me it looks like not enough moving air in your room and the light is almost burning them from heat.

If this room is in a house where people live please be very carefull with co2. It is heavier than air and can flood a whole house and kill everyone inside.

Co2 really only helps take a week off of your harvest time. If you just need a trickle to get co2 levels back to a little better than normal because you don't have a good source of air then it's the stuff.