Don't forget that a properly balanced diet will provide adequate electrolytes. All the same, I usually add something to my water just to be sure.
I am currently using various Nuun tablets. Looking at a label, they state15 calories and one gram of added sugar and of course all the good stuff - calcium, magnesium, etc.
I started using electrolyte supplements when doing marathons and other long runs. I found that Gatorade did not sit well when running hard, although I can tolerate it when at a hiking pace. Diluted 50% with water, it did much better