Something I'm curious about I know it would end up costing a pretty penny but design of a rough and relatively porous block to house back think reef safe plastic 3d printed marine pure blocks just a random thought
Like this?
https://www.reef2reef.com/threads/3d-printable-live-rock.244296/
This was just an idea and didn't come into fruition, and with printable plastics it isn't really a realistic goal.