Why caring?

To explain what follows here is a picture I took this summer -it's more or less the kind of effect I want to acheive with this diorama. When the water is flat it *is* flat. the problem with the resin is that it *shrinks* which produces a crap effect when you immerge partially elements in it. Even more worrying is the fact that it never looks like a flat water. it creates some sort of uneven bumps -which ios really okay when you want to create a sea, but not it you want to create a pond-like water!