yellowing leaves from too much light?

[ur420ducks]

hi everyone I recently saw that the top leaves of some of the biggest plants that are directly under my lights have started to yellow. I am am in 2nd week of flower, using 2400w over 40 sqft in flood tables with ro water and added calmag, hg full line ph to 5.8. The temps stay around 70-80 night n day and there is a good amount of air circulation. I noticed that the only plants that are yellowing are directly under the lights and they have very tight internodes. All the plants that are around them are nice and green. I recently had a mg deficiency last week that I took care of by upping the calmag and saw good new green growth and now only the some(the ones under the lights directly) are yellowing at the top. my question is should I up the calmag more? or raise my lights more? a third option is to rearange the lights for better spread and less direct light but that isnt easy with so many plants. sorry for no pics as i dnt have a camera that does it justice. would love to hear peoples opinions thnx

ps i add 13ml of calmag plus to my ro water bringing the ppms to around 200 before i add nutes

 

[RetroGrow]

Does sound like light burn, which will happen to plants directly under high intensity lights. Pictures would help, but the fix is simple: move them a bit furtur away. Put your shortest plants in the center, and tallest plants on the outside.

 

[B. Friendly]

if you put your hand under the light near the leaf in question, does it feel really hot.

Yellowing for leaf burn would not look yellow as much as it would look like something shrivilling looking.

if it's just yellowing of the leaf and lower leaves then it's nitrogen deficiencey

 

[RetroGrow]

There's a difference between leaf burn (heat) and light burn (radiation). Light burn will not shrivel your leaves, but will leave them yellow.