It has pretty much started to kill them. They are dying from the bottom up. Plants are roughly 1 ft tall and the bottom two sets of branches have started to wilt and dry badly. The upper top 2/3 is almost looking water deprived with a lil nute burn. However the soil has plenty moisture and the nutes are right where they should be. I plan to give them a health feeding today and wait for signs of recovery before i get the co2 going again. I dont have a digital controller which is why i am confident that i am dealing with Co2 overdose.