WHat is causing this?

I believe I had a little salt build up in my medium which is coco coir but I have flushed with florakleen and the water looks clean coming out but it still seems like the plant keeps eating itself with all these brown leaves then they fall of just wondering what you guys think is causing this I only really have this problem with huge plants like this. Nutrients are advance nutrients conno A+B ph perfect with additives RO water strain critical kush 5 gal coco coir smart pot day 26 flower leaves are droppy in pic from not being watered for 3 days normally water every other day but missed a day.

your plant is thinning itself to areas that cant get adequet light... its fine... you said your feeding it and the rest of the plant looks overall healthy

All of mine do the exact same thing. The thicker and taller my plants get, the less light those bottom fan leaves are gonna get. Those fan leaves on the bottom just seem to die off on their own. But new growth seems to promote not too long afterward. I think you should be fine. I haven't changed anything in feeding my plants except maybe making it a lil stronger. And my plants are still nice and healthy.

Looks to me that they are dying from lack of light, that's normal for lower leaves.

k cool I thought I might have been doing something wrong

Riu gottcha covered, all good.

natural selection.