OK, so it creates more , that's cool. So why does it return to your hand exactly? Doesn't this + quantum pillar + water dragons do too much?
Fire, Earth, Air, Light, and Life have creatures as alternative towers; I wanted to give Water its own alternative not involving creatures. It requires other quanta to work, so 1 Quantum pillar would probably be enough. That's why there was discussion to raise the activation cost.
As far as it being OP with Ice Dragons, I don't think it would be. It's vulnerable to PC until you activate it and PA's would be useless because it is removed when you activate it. As it is listed right now 3 --> 6 it is equivalent to Rustler. Rather than being able to use it multiple times in a turn, it does a "splash" of production all at once. And then you have to wait 2 turns before you can use it again.
The deck out prevention (returning to your deck) is similar to Eternity and symbolizes the timelessness of the ocean and how it takes eons for erosion to occur. Here the other elements are being eroded.