Acma:Game - Vol. 8 Ch. 61 - Pour to Limit

[MangaDex]

 

[vangstampede]

The owl judge is a dude wtf

 

[gormadoc]

"Hoot hoot! I'm the game master."

 

[Woodchipper]

They're probably going to use their abilities to get the other to trip up by either getting the water to 4°C for maximum density or teleport the space to reduce air pressure to make it expand when the other one is pouring.
I also guess the containers are single use only, considering there's multiples of each.