you're sure about that, I never heard of that before, and I read a lot of this stuff, if that's true I know some people who might have to switch to organic...and I use organics so it's not a salt buildup...
Thanks for all the ideas guys. Turns out it was a basic but epic fail on my part. I had the smartpot sitting in a little runoff tray so the roots at the bottom weren't ever drying out and not getting sufficient aeration....which resulted in some nasty anaerobic stuff growing and killing my roots.
I discovered this by lifting the smartpot up to see the condition of the roots that came out from under it and was greeted by the smell of rotten eggs. no bueno!
So now I have it elevated on a grate over the tub like I should have from the beginning and will let it dry out before giving it another water.
Will also snap some pics when the lights shut off tonight.