If you decide to make your own edible water bottles, I'd recommend adding some sort of sweetener or flavor to the sodium alginate mixture, even if that made juice bottles rather than water bottles. Or you could try to remedy the texture by using a reverse-spherification process: Put scoops of the thinner, more drinkable calcium lactate mixture into a bowl of sodium alginate mix, instead of the other way around. This might produce a drink that's more like water and less like goo. (I would try it myself, but I ran out of taste test
victims volunteers). If your experimentation yields more palatable DIY water bottles, then let us know! Send the recipe to firstname.lastname@example.org.