deficiency is not always lockout, most of the time it's just the plant needs more (N) then the others and that's all.

There is a cycle feeding chart in the FAQ for GH 3-part nutrients.

Flushing is normal in Hydro for 48-72 hours keeping the Ph balanced.

I never said it was locked out. But miss balanced Ph is the cause most of the time. There is a Ph chart in the FAQ you should have a copy of on your desktop.

You don't need epson salt all the time, I use more H²o² then epson salt 5ml per gallon with every water change for vegetation and flower up to the last 3 weeks of flower then I don't bother.