The pressure in a fluid depends only by the deep $h$ and the density of the fluid $\rho_f$:
\[p = \rho_f h g\]
where $g$ is the gravity.
We could consider also the generalized stevin law
\[p = \rho_f h g + p_0\]
where $p_0$ is the atmospheric pressure at sea level, but in order to explain the starting sequence in the following animation the first equation is sufficient.
Thanks to Leonardo Petrillo (twitter, GPlus)
