No need to panic. First thing to do is check the heat at the canopy top. Even though you're using CFLs that 250 is still going to give off a bit of heat, especially from it's ballast. Hold your hand at the canopy top, palm down, and see how the heat feels on the back of your hand. If it's comfortable for you, it's comfortable for the plant. If it feels too hot, raise it up till it feels comfortable.
I doubt you have overfed them, given that you are still giving about 1/4 strength, so next thing to check is your pH. If it's off it can cause problems that can mimic deficiencies or other issues. What's the pH of your run off? Until we know that I wouldn't do anything else.