hi tyler,
few things come to mind.
1 - do you normally leave that filler cap extended? (bottom left in the picture)
2 - whats the pH of the water?
3 - whats the ppm of the solution?
4 - (i assume that you do, but) is there an air stone in the bucket?
something points to an unhappy root zone, thats for sure.
any air movement, with a fan?