I think I heard someone here say something like 400 ml and no less, or else smaller amounts of water cause the ball to hit harder inside the container, and therefore more likely to crack. But a guy in a Facbook Kava group said he uses much less water than that, so it's a stronger grog. So I'm confused about the safety of using small water amounts. And I don't want to crack my balls, or burst them. What's the consensus opinion here on the safest minimum amount of water/liquid to put in the bottle ?