Products like Alacer's electromix have the electolyte part down very well, and are easy to bring with you. A complete solution, perhaps the best I've seen, is H2O Overdrive.... see h2ooverdrive.com
When used on a long diving day, I stay perfectly hydrated so deco issues are safer, I don't end up feeling weak or hungry after each dive, ( drink it before and after each dive) , and I have far more energy AFTER diving for the rest of the day....could be less osmotic stress from better offgassing with optimal hydration---could be just better nutrition throughout a dive day--less fluctuations of blood sugar, and the after effects low blood sugar will provide.
DanV