I think there was just geo's flicking but Mrs said she sure they was doing that beforeadding direct to the tank wont hurt anything unless the fish roll around in it while it dissolves.
WATCH the geos and cories, if they start flicking hard do a water change and switch to using a med like paraguard instead.
Temp is enough. Unless you have a strain that is resistant. Super ich?Can high temp kill white spot with out salt?
If I do a 50% should I add salt back in or not