ECONcrete: Protection from hydrodynamic forces while generating marine habitat

They must have a way to stop it leeching calcium.

when you have concrete in a pond, you have to seal it, otherwise it poisons the pond (and gets frost damage). The green wall application leads me to think they've overcome this.

Bloomberg video on how it works: https://www.youtube.com/watch?v=YGJ5EBrh8IQ