Describe a strategy that can be used in electroplating to maintain the concentra

You need to keep a near constant amount of Ni2+ in solution, so you can run

Ni2+(aq) + 2 e- Ni(s)

for an extended amount of time.

I would put an surplus of a Nickel salt into the vat. That way when the Ni2+ is plated on, it will dissolve more of the salt. Eventually by the Ksp relationship, the Nickel level will drop unless you can find a way to remove the associated anion. One way to do this would be to boil off the anion in its acid form. Another way might be to precipitate it by having another cation in there, but that could run into problems with another metal being plated in addition to Nickle.