Then it must be a freshwater algae, similar to when the ponds are full of that duckweed. I'm a child of the Baltic Sea, I know algae pretty well... I'm not giving up hope. Every now and then they do work 😉😁
Do you know how watering cans with leftover water smell when they've been sitting for a bit too long? That's what I mean. I still haven't figured out exactly what it is for me; "marine notes" are never very helpful.
A really nice brackish scent for me is "The Dark Side of the Water."