I was thinking, “why don’t they use geothermal energy for water desalination?” I looked it up and apparently they are trying as a proof of concept was proven to work. https://en.m.wikipedia.org/wiki/Geothermal_desalination . I have a feeling this may get mysteriously “shelved” and the Tidal Energy platforms (reported on by the Smithsonian). We could build under water chambers by creating volcanic brick pyramids around a vent. We would then create a vacuum using suction and compression and a loop line. The chamber would be separated theoretically by up and down walls that are slanted from the bottom towards the side that will be sea water. The loop line would be at the top platform and the saltwater intake would close (if creating a multiple chamber system for steam wouldn’t take out all of the salt) and the loop line would repump through the water continually. I am not sure if salt sediment would cause problems with vent health or not?) By using a pyramid shape with bricks and double layering them we can create a heat funnel that condenses the heat to a chamber that both the loop line and sea water intake valve. It may need to be a three stage system (I am not a chemical engineer so I am guessing) or having the steam side have another angled ceiling and suction. You could probably calculate the slant of the roof based off of fluid weight to where lighter water continues at the far side to the suction line and heavier water falls back to the chamber. You would probably also equip the suction line with a demister pad. Im sure the current way they are harvesting clean water is probably more efficient than what I’ve outlined but using underwater vents could potentially revolutionize agriculture and provide more sources of clean water via aquaducts and channeling. The Tidal energy platforms if built facing opposing directions of the currents of vortices and format them to be long channels. These two things would improve the garden project and everyone’s lives, so watch that these aren’t “shelved”.