You are quite correct. My error. It is velvet.
So, what's the answer? You seem to have the knowledge I seek.
What is the correct SG/T for treatment of cryptocaryon irritans.
My current understanding is 8 weeks will cure the display tank providing it is free from fish. This is similar to fresh water ich, break the cycle.
What about the fish? Obviously medication free treatment is better for everyone.
Well in a qt it would be 1.009 but you would need a refractometer to do hypo you can't do it with a regular hydrometer and you need to lower the salinity slowly,or you could use copper cupramine is very good and you'll need a copper test kit one that tests free or ionic copper and 8 weeks should be enough to kill of the ich in your display. Remove the fish from the display and you can keep the inverts in there. Just remember you can't do any of these treatments in the display tank.