just pulled up the roots they are not slimy or weak, they feel solid and they are milky white. A couple days ago i added another 2 teaspoons of cal/mag to all of them. 3/4 started to grow more and slowed down on necrosis but one still is stunted (back left pot). Maybe calcium lockout? Too much light? Would too many bubbles/oxygen affect them? I had the pump on max with 2 4" air stones in the one with most symptoms. The other three have 1 stone in them, Coincidence? thanks for the help