What you're seeing is, I believe, a phosphorus deficiency and your nutes aren't giving the plant much of this... add to that problem, I don't think you're giving her enough water if you're only giving her .05 gallons a day... so what's happening is that the nutes and salts aren't being flushed out of the soil and are building up. I would do two things: I would flush her out with 3x the pot volume of pH'd water (your pH is terrific - no worries there!) so for you, that would mean 12 gallons of pH'd water through the pot. Into the LAST gallon, put 1/2 strength nutes to include a PK boost... General Hydroponic's KoolBloom liquid is what I use, it's NPK is 0-10-10. (Be careful with any PK boost as too much of a good thing can turn out to be bad!) Then, when she's dry, give her another plain watering and then you can resume your nutes at the levels they are now... but keep the PK boost going. If you use the GH KoolBloom, they have a dry formula of it that is only used during the last two weeks (if memory serves) of the grow - the liquid is used from where you are now in your grow up to those last couple of weeks...
And whenever you water, make sure you're getting about 10-20% runoff... this will help clear out any excess nutes and any salts that might be building up.
Good luck!