I'm trying to make a sealchamber that close the door when filled with water.

Here's my attempt:


The first room the switcher is off leaving the room open.
The second room I put a sand particle just to show what I want
The third room is what happens when I tried to use this room with water. A loop with spark bugging the system.

Any tip?

I'm trying to use this in a salt walt distilator, so it needs to be salt water(which conducts electricity).

Updated.