i wouldn't concern myself if the hairs are turning. unless it looks like she's dying. really when i say brown, it's the leaves. how late are you into the grow?
suggestions...
-maybe grab yourself one of those cheap pH meters. the green ones with the metal probes. not real accurate, but will give you an idea what you're dealing with.
-if you can, check the pH of the water you'r using.
-if you've got less than like 4 weeks left, i wouldn't bother with nutrients, maybe toss some composted soil or potting soil, that's got nutrients in it, on top and water.
-do flush your pots. straight clean water. just let it run through into a bucket below. that seems to solve many problems. (truth be told i need to flush more than the one time i usually do)
when it comes to nutrients, you don't need the most expensive stuff out there. i've used miracle grow before. actually a buddy of mine grew a 6' plant in his basement with dirt out of his garden, some sand and miracle grow. he watered with well water, on top of that. haha.
if the pH is up, make a water:vinegar (10:1) solution and add a bit at a time till your pH is down. if it's too low, baking soda will help to a point. from what i've read you want your pH around 6-6.5.
i hope that made sense/was helpful.
grow grow grow!