The best holder I've used
I've used the Fishpond floatant bottle holder for years and love it. In addition to being solid, secure, and good looking, holding the bottles upside down keeps whatever is left ready for use. Just remember changes in atmospheric pressure when you hike into that high altitude lake or stream - if you don't give it time to settle to the bottom of the bottle, you will get plenty of floatant when you pop the top!