How does one optimize the molar concentration of electrolyte in terms of the rate of electrolysis?

There are many textbooks/recipes for various electrolyte solutions in the electrolysis of water. I know there is a minimum voltage to kick off electrolysis, and I'm supposing a minimum concentration of electrolyte like $Na\_2SO\_4$. 


But isn't there an optimum concentration of electrolyte that maximizes the rate of electrolysis? Are these recipes based on that optimum, and if so how can one calculate what that would be for any given salt or liquid electrolyte?


