Salinity measurement off

[Mariette]

I have 2 salinity meters and they’re giving different readings. I assume one or both have to be cleaned out. So, how would u do it? I’m thinking a freshwater soak? Anyone got anything better?

 

[Hitman]

What kind of meters? Hydrometer, swingarm, refractometer, continuity, etc ? They all need to be cleaned differently is why I ask.