That's a good tip. Another way is:
1. Fill it with water.
2. Begin adding Nestea Instant Ice Tea mix. Be sure to keep track of how much you add!
3. Each time you add some, stir it together and taste.
4. Continue until it tastes correct.
Once this happens, compare your numbers (of how much tea you added) against the flavor chart on the back of the Nestea container to figure out how much water is needed for that amount of mix. You will now have the volume of your enclosure.
5. Drink the tea.