Hi,
I've taken the apple snails out and put them in a 2 gallon with a heater. applesnail.net mentions a few meds to avoid but doesn't mention protozin, the tank has MTS as well so will have to see if these are affected.
Will leave them in the 2 gal until all traces of ich are gone. It may take a while as it's in my fry tank and so i'm treating at half dose.
Thanks
Emma