KebinLub is that your Runoff ? 6.5 If not check the Runoff I just water till it comes out the bottom holes and then test that.
And if that's the case I suggest you flush them out with about 3 to 4 times the amount of water to your pot size, Say your pot is 5 gallon you would need 15 to 20 gallons of water to flush properly. Then what i would do is give half the nutes you usually give, You can work your way back to a normal feeding then. I am pretty sure ffof is hot off the get go so IMO.
Give them about a week they should perk back up.
Good luck and Happy Grow. Peace out