Hi again,
Hard to get a picture from it since I don't keep my stuff in my tiny room ^^'
Here are some pictures I found on the Internet for the "artificial water" which is based on epoxy:
When you apply it, it is somewhat blue:
artificial water during application
After it dries, please not that it is for modelism: we use to paint the ground under the artificial water in order to give an other more natural color to water (like green or blue...). I didn't found a picture where you can see "artificial water only" but based to my experience, it is completely transparent.
artificial water ready
For the distorsion due to glue or epoxy solutions, it will have almost the same aspect than if you did put water in your box (slightly different of course but it is still transparent).
If your box is in plexiglas or some plastic stuff, be really careful with the epoxy (it attacks polystyren and other plastic, making the plastic going white and dusty, not exactly the effect wanted). Dont use every cyanoacrylate glue (called in french "super-glue", I guess it can be the same word in english ^^): it simply makes a hole in polystyren and make other plastic turn to white too.
So, if you're aiming to use epoxy: check the material of the box and look on google if there are any undesirable effects.
If you're aiming to use glue based mixture: don't use cyano acrylate but PVA glue (no distorsion or chemical problem with it).