One of the challenges posed when using drink dispensers is figuring out how to keep the drinks cold over several hours. The first time I entertained with drink dispensers, I popped down to the local bottle-o for my trusty $3 bag of ice and poured half of it in the dispenser. Sure, the thought was there but after a while instead of tasty iced tea, I ended up with a diluted disaster
Needless to say, I now make my own iceblocks, using flavours from the drink itself so that as they melt, they don't dilute the rest of the drink. I like to include pieces of fruit or herbs in my blocks, if suited to the drink. It adds extra flavour and of course helps things look even more amazing.