Valvenis,, I know you're trying but you've actually lead this thread away from my actual problem.
It's ONE plant in a 5.5in pot and I'm sure I'm not overwatering, I've done grows in small containers before. Yes they do get rootbound, it's a prospect mother plant so I want it kept small, if I wanted it bigger I'd trim the root ball and toss it in a larger pot. I didn't have this problem with my OTHER grow which was even more compact, so I'm convinced the problem doesn't involve my watering or pot size.
Salt buildup is not a likely culpurit either, they were all flushed before my last feeding.