Note on additive water: ALWAYS provide plain water (no additives) at the same time-they can choose.
Second important note in your situation: do not leave the electrolyte water out all day bc microbes think it is delicious too. The water will go bad and may cause unintended illness.
If your vacation is a day or two away. Give them ample opportunity to get electrolytes now. Give them plain water while you are gone. Then, when you return, you can give them electrolyte water again. Generally, you do not offer additive water more than 1-2x per week anyway.