Nice use the the rule of thirds. Great detail in the shell. I wonder if this would be better with no water because the movement of the water detracts a bit from the shell in the top right corner.
Nice patterns in the shell, but your title is presenting this as a study of the water itself. The water is almost invisible it is so insignifigant in the shot. At the same time, the interesting patterns in the shell are not taken advantage of in any way which allows them to define the photo. I feel like there are two thoughts here, neither of which is strong enough to pull me in but either of which might do so if presented differently.
Just lovely. I think all photographers should have at least one of these in their portfolio. Such a simple and elegant thing to do. And of course, it breathes summer!