Maybe I missed it, but what are your nutes/tea?
She's missing out on something, probably a minor/micro nute.
Doesn't appear just to be cal/mag related, though that might be an issue too - if the other minor/micro nutes aren't there to compliment the major nutes, plant will have issues.
Teas are wonderful but until you have DWC down, I wouldn't recommend trying to make your own.
I run a hydro room, and run General Hydroponics 3-part - why, because it works and it's easy.
Once a week I add some hydrogen peroxide.
The other brand I would recommend for Hydro (works fine for soil too but one can brew teas for soil just fine) is Dyna-gro - it has all the minor & major, along with cal/mag. Even though one may still need to add in Cal/Mag generally with Dyna-Gro with some strains.
Also what are your rez temps, rez ppm before & after adding nutes?