lower leaves starting to fall off

Hey everyone, the last few times Ive exchanged my water Ive been noticing more and more leaves are drying up and falling off. I am in my second week of flowering and am just hoping this is part of the process and not lack of light or something else. I am using 8 42watt bulbs and 4 27 watt bulbs. However because of space most of the light is coming from the top and not on the sides. thanks

mine was doing that to.....they were really rootbound, so i transplanted

I dont think its that cause Im using a bubbleponics set up and I can see when I change the water the roots are massive but they have plenty of room still

It's normal for that to happen. Just pull um off ot do sum prunning on sum of the dead or dry leaves at the bottom.