You site the can for five, over them bottom and cylinder in the sea, and connect a vacuum pump at the top. We draw out the water and initially all goes well. Through our viewing ports, we can see the water rising.
Then at 6 feet the water begins to boil. So the water, stops rising and refined that we are evacuating air and water vapour. After 10 minutes we are trying out pure water: which we pump through a pipe to a reservoir.
Its salt gets left behind, and exits the tower as brine water. Although it sea water is drawn in to replace it. We have decelerated sea water. This will even work at the dead sea. Anywhere on the sea you have access to pure water for ¼ the price of high pressure desalination.
Farmers can he crect such a tower in 2 hours. And have access to limitless fresh water without paying higher charges two water company. A vacuum pumps are very cheap to run. In contrast high pressure plants are horrendously expensive to run.
We have no filters to worry about. Portugal can make all the fresh water it desires, as can the Middle East. Israel can pump pure water out of the salt laden waters of the dead sea.