Help newbie in flowering

I am having a problem with the leaves yellowing light green an spots browing then leaves crumbles up in using Fox farm soil an general organic go box for nutrients the problems just started have been having a great grow till now

how long has she been flowering?

Around 3 to 4 weeks ago maybe a little longer

Wish you had a little better idea of flowering, but thats ok. I've come across with mine, that what i like to call the under leaves that don't get no light, that will sorta shed in a since and wilt off. I'm in my 5th week of flowering going into my 6th, and i usually find a few on the inside that are like that. Maybe there is a problem, but i really don't see it, according of what i'm seeing at the top of the plant. Just my opinion, maybe some of the more seasoned people willhave a better idea...

Mine runoff ph is 6.5 to 6.7 900ppm. I water with tap water at around 36ppm

They hungry...need some N

@dbmoney, I think Porky is right. The plant will pull what it needs from the lower leaves during flower but you still have a long way to go and those plants are starving. Feed me, Seymore!

@BudmanTX, nitrogen is a mobile nutrient and will show an insufficiency first in the the lower leaves and work its way up.

How much nitrogen would i need to add to begin with i think my bottle of grow calls for 1tps or tablespoon per gallon of water im not near the bottle to see witch one it is right this min

It's hard to say without knowing what and how much you've been feeding. You don't want to cram a whole turkey dinner down a starving girl's throat but you could def try bumping up the nutes a bit. Your run off pH is perfect.

In some product lines you'd only be using Micro and Bloom at this point.

Needs N.