Light intensity question

those plants are old enough to gas it... keep pushing... You have a fce3000. this is a powerful light made for 12/12 schedule and a 3x3 space. that light on an 18/6 can cover 50% more. 9 * 1.5 = 13.5sq feet. so a bit over 3' x bit over 4' is a good footprint that properly hits the edges and corner (free lux app on phone can help here) ... it'll probably be at least 24-30" away if you want to run at 100% for 18 hours per day. becareful with this light on a 18/6 schedule. Use the spec sheet suggestions for vege cycle as far as area of coverage. prolly want to push that feed to 650-750ppm (either calculated from labeels of products used or an EC pen on a 500scale.. EC is the same between products but how those TDS pens calculate ppm from EC differs -- 1.3-1.5EC is safer suggestion that won't differe based on equipment used) you'll be providing about 40DLI if you have it set up right for the area. this is about as much as you can provide per day given ambient co2... this isn't meant to be written in stone... you still have some trial and error left to do through observation and reacting to the plants to learn where that upper boundary is... lack of light is easy to see... length of internode will quicly tell you that. too much light, if barely so, is more difficult to see. sometimes tehy look find for 2-3 days after increasing intensity, then at end of week you notice severe drooping at end of day for long periods of time... sometimes it takes a few days to build up, if giving too much light. a delated effect of the cause is more difficult to recognize. so when you make a change, give it time to react. take notes to avoid the process next time, or at minimum slim it down to a simple adjustment per plant genetic / slightly different environment each time you grow.