You are correct in your observation regarding the anchor wash system in my SM.
So, I already discard this option.
Regarding TDS test, I did not made the accurate test.
I order a TDS meter, but the taste is salted, no color or smell.
As long as I observe, the first place to show the seawater (assumed) is where you mark the green area.
Can you help me to identify this hose (picture) that comes out of the bow and passes under the floor of the front wc .. Its entire extension is moist with salt water, despite being attached to the top of the floor.
Thanks for the help
SV Wayag, SM 323
Currently Alicante, Spain