In reverse order - the simplest way to determine 125 ppm N is to divide 10 by the %N in the fertilizer, giving you the teaspoons per gallon to add. It's not dead-on, but neither is the calculator!
Going back to the original problem, I'd bet it was poor timing of the repotting coupled with a fairly drastic change in root zone environment.
- As roots grow, the cellular structure tailors itself to work best in the environment in which it's growing.
- Once they have grown, they do not change.
- When we move plants into a new - different - root environment, those cells will not perform their function as well.
- The degree of "disfunction" is dependent upon how disparate the old- and new environments are.
- Repotting a plant when it is actively growing new roots gives them the opportunity to tailor themselves and support the plant; the old roots may not be able to do so, and if there are no new roots coming, the plant will suffer as described.
The thing to do is NOT to repot again and stress the plant further. Instead, you need to reduce the stress it is experiencing:
Leaves shrivel because the plant is losing water faster than it can take it up - the less-than-ideally-tailored roots are not "cutting it", but the chemical processes in the leaves continue. In order to improve the balance, you need to slow the moisture loss through the leaves, and that's where the old, reliable, "sphag-'n'-bag" technique comes in.
Put the plants - pot and all - into a clear plastic bag and close it up. They are then in nice, cozy mini-greenhouses where the %RH will be maxed out, and the moisture-extraction driving force will be reduced, if not eliminated.
Keep the plants warm (I prefer a minimum of 70°) to accelerate their metabolism, and shady (to prevent "sphag-'n'-bag" from becoming "broil-in-bag"), and they should recover nicely.
A couple more things to consider:
- All those "bullet points" above apply to ALL repotting jobs, not just those involving moving them into semi-hydroponics.
- S/H-to-S/H repotting can be done at any time, as the new- and old conditions are identical, and as that usually means just moving the root mass-and-medium to a larger pot and adding more medium around it, the roots are undisturbed.
- The same is not true for any medium containing organic components that can decompose, as the old- and new conditions will never be the same, and you'll probably do some damage as you pry the old medium from the root mass.
Lastly - and I don't know if it applies in this specific case or not - quite often, folks will struggle with their plants, gradually weakening them due to the stresses of less-than-good overall culture, then move them into S/H culture in hopes that it is a "magic bullet" that will cure all ills.
It's not. It won't.
What they have unknowingly done is take an already stressed plant and applied a great deal more stress (for the reasons described above), so the decline accelerates, they blame it on S/H culture. Some think they will improve things by moving it back to more "normal" culture - which often kills the plant. Been there. Done that.