That depends, if it's just the bulk of the water aboard the ISS as a floating sphere and in the absence of forces that may create a gradient then I agree. Once a bubble of air is introduced into the sphere then to be honest I am not so sure the parameters remain the same.The pressure within the bulk of the water is constant. Accordingly, the pressure gradient is zero within the bulk of the water. That is what I mean when I say that there is no gradient within the bulk of the water. It is not clear whether you disagree with this.
You will end up haveing two different substances with different properties and densities one on the inside of the sphere of water as air and another on the outside of the sphere also as air.
Also two layers of surface tension.