are zero calorie drinks ok

Hi, Gmoyer3292. Regular Crystal Light uses an artificial sweetener, Aspartame, so it is not recommended here. Artificial sweeteners have been shown in research to actually work against weight loss by confusing your metabolism. The company does have a version called Pure with Stevia, which is better.
A good alternative with less of an aftertaste would be mixing a few squeezes of lemon and/or lime juice with water and a natural no-cal sweetener such as monk fruit. If you like flavors other than lemon, try a natural fruit tea with monk fruit and cool water.