redox improvement with reducers

im aware with the addition of uv sterilisation , electrolytes and reducers such as calcium and magnesium to increase the redox value the tanks health is at an optimum etc just wondering has anyone dealt with the addition of calcium and magnesium in purer forms in relation to aquariums as i am mindful of how reactive they are with regular tap h2o ,( bubbles a plenty )

There are loads of reducing and oxidising agents.

eg acids are oxidising agents (a definition of an acid is one which accepts an electron pair); methylene blue is the classic redox indicator (because it a redox modifier) in medication.

However, the notion an oxidising agent vs a reducing agent is relative (just like the notion of an acid is relative). eg Compound A may be 'a good oxidising agent' but when put in with fluorine atoms it may just become the reducing agent as fluorine is likely the rip the electrons from most things.

But it is not a simple matter of 'increasing' redox potential as that has no real meaning.
It all depends on whether you are trying to increase a reduction potential or increase an oxidation potential.

More important is RedOx balance.

In freshwater the RedOx should be between +125 (Ox) to -200 (Red) mV;
In Marine Water the RedOx should be between +300 (Ox) to -100(Red) mV

If the values extend (decrease or increase of voltage) beyond those levels then the health of the fish suffer.

If you added metallic calcium or metallic magnesium to water then the reaction would produce strong bases, and the pH may well shoot to a high level if the amount added where too much for the buffer to cope with.

If you require general health within the fish, then a reducing environment is the aim.
If, however, you need to have healthy water with a reduced microbial count then you aim for an oxidising environment.
But if your water has an increased Ox Potential to make a low bacterial count, then you run the risk of compromising the fish health; the fish will need anti-oxidants (such as the reducing states of calcium or magnesium) as the ideal biochemical environment is a reducing environment.

Does that sound complex? it is.
RedOx is yet another item that works on balances and not necessarily on absolute values. One aspect has be oxidising whilst another aspect has to be oxidising.

In whole theory of thermodynamics, it doesn't really matter how the balance towards equilibrium is done so long as the end sum creates enough free energy to do useful work and that energy systems become as distributed as much as is possible (it isn't as simple as that....but we are talking about entropy).

Personally, adding magnesium or calcium metal would not be a great idea.

ian