I fill a bottle 1/4 or 1/5 full. Then freeze it. Next day I fill up with water, add a little of Colloidal Silver
(to avoid a build up of bacterias) (trapper knows how to make it, I buy it)
-Then it keeps cool for the day.
My boys have had this for their school drink for years. Periodically I have made lemon or black currant lemonade in addition to or instead of the water. With Iodine
in it of course :)