GU Hydration Drink Tabs, Tri-Berry, 8 Boxes of 8 Count

I like the taste of these, and I think they do provide some extra benefit for sports hydrationI'm in Arizona, and typically freeze my filled bottlesOccasionally, these (being carbonated/fizzy) can produce some unexpected resultsI've learned to fill water to about 3/4 level, leaving room for expansion during freezing, and don't tighten the caps all the wayUsually that works, but a couple of times even that has overflowed quite a bit, leaving a slushy in my freezerI guess that there may be variation in their recipe for fizziness