Hydro, hydro mesh, Kangaroo

Hello every one,

I´m starting whith grasshopper and it might sound dumb, but im having a really hard time trying to emulate a bag full of water whith "hydro" component. Can any one give me a clue or an example. I was able to do it whith the "pressure" component (gas) , but couldn´t  whith the "Hydro" depth dependent pressure (whater) .

best regards from Chile.