i think you need calmag+ with the ro water... a ph test wouldn't hurt either, get some cheap strips and at least you get an idea of your ph going in and coming out...

and instead of cutting my fan leaves, I tuck or tie them down to expose bud sites (I do LST and now Scrog anyways). The plant takes nutrients from the fan leaves, which absorb the light energy and store it for the dark cycles. If the leaves on the bottom turn yellow, its usually normal. They just aren't getting enough light and the plant is using up the remaining nutrients. You should only pull leaves when they snap off easily with a slight tug.