Yellowing from the bottom up

I have this 3 foot Sativa plant that has always been difficult, its kept because it is a female. Its been kept in soil its whole life (about 4 months), and was fine until the last 2 months, when I transplanted it to its permanent home.

heres a pic! as you can see most of the lateral leaves have fallen off, I need to fix this quick!
-Ive already flushed it with 2 gallons of Reverse Osmosis 6.5 ph balanced water yesterday.
-its under a 1000 watt MH it seems to like it.
-as you can see there's supplementary flourescent side lighting.
-Ive recently switched it to RO water.

PLEASE HELP!! do you think its nutrient lock out?

what kind of nutes are you using? and what kind of soil...looks like N deficiency

it may be the RO water. but looks like a nitrogen deficiency

this is what i was dealing with i have also started with r/o water , i got the report back from the city my water is a PH of 7.6, i've been poisoning my plants i've already seen a diff in the plants and its only been a week

i dont think its the RO water this started much before that, but seriously N definciency? that usually comes up as washed out leaves I had that with some test clones of a plant I jacked off of Whole foods lol.

as for the soil, the main bulk is foxfarm light warrior, to fill in the rest is some innocuous brand, I think there may have been too much nutrients in it, as for nutes istelf. I have a variety, but ive been keeping it away from it because it ended up burning really easily, got the dead tips. =(
please keep up the stream thank you!

no RO has nothing to do with it. Yeah, seriously N deficiency. http://www.icmag.com/ic/showthread.php?t=11688 it's yellowing bottom leaves which is exactly what you have. give it some food. light warrior is very mild solid, suitable for starting seeds, not for growing a plant while keeping nutes away from it....

thank you for the info, one last question, even if its starting off with brown spots first before they yellow and fall?

I really think that's the problem, but I certainly could be wrong. I don't see any real brown spots on the pics, just maybe 1 or 2 tiny ones, I do not think it is nute burn if that's what you're wondering. Good luck, if it was me I'd give them a light fert of N and see what happened in the next 3 days. If they yellow increases more rapidly then it is not N, if it decreases in rapidity, then try a slightly higher dosage. If it stops, great!

another point I would like to make, is that the browning isn't occurring from the tips down its in the middle of the leaf interestingly enough, I'm inclined to believe the N deficiency since i've just been doing water for awhile. any more theories are welcome, I have until tommorow.