Dirty Salt?

[asylumdown]

I think your'e seeing that because it's a static basin that salt water is being mixed in before being moved somewhere else. I've been using H2Ocean for the past year. I keep a 44 gallon rubbermaid of it in the garage that I use for water changes on the pico tank, but do all my water change steps (including mixing of the salt) for the big tank in a dedicated sump chamber that gets put back online with the rest of the system when I'm done.

The rubbermaid is rapidly developing a gross crust just like that, but the glass of my water change sump chamber is as sparkling clean as the day it was built. Whatever does precipitate out of your salt during the mixing process falls out of solution in a separate basin like that and stays there, but if it's mixed in a vessel that will then go inline with a bigger system of water circulation, the precipitate will eventually dissolve back in to solution.

Does vinegar dissolve that gunk you're seeing?