[powerman]

I am looking for different compounds to speed the production of Hydrogen and Oxygen. 

I am wondering in particular about epsom salt if anyone can give an insight on it?

Thanks a ton in advance.

Powerman

[Arkcon]

If you're looking for an electrolyte to improve the conductivity of water that you're electrolyzing, than yes, magnesium sulfate is a pretty good choice, and will speed gas generation.  Neither ion -- Mg, nor SO4, is going to be electrolyzed instead of water, unlike for some other cheap, common salts, for example, table salt.

[pzona69]

I know this is unrelated to the original question, but why won't MgSO₄ electrolyze? I was looking at it as a possible source of the sulfate ion for making Cu₂SO₄, so I'm guessing that won't work?

EDIT: Could it have something to do with electronegativity??

[Borek]

but why won't MgSO₄ electrolyze?

In simple terms: because water gets electrolyzed more easily. Check with the reactivity series and/or potentials of half reactions.