Because the device is tilted, saltier water flows out of the device and back into the main salt water reservoir due to having more mass than the less salty water. As long as the main reservoir was regularly flushed with new salt water, it would never become dangerously concentrated to marine life, which is a major advantage.

Eat it

Sea salt is also a possible source of lithium, so you could possibly mine and filter it for various resources.

If you can get it dry enough, there are huge underground salt mines that could be back filled.

But an larger ocean usually has enough currents that it dillutes out well enough to not be a major issue.

It's shot in to space!