That sounds more like a salt dip method that I used to hear about for parasites, but I haven't heard anyone doing that for at least 10 years. The heat and salt ich cure typically involves raising the temperature in the tank to 84-85 degrees, adding 1 Tablespoon of salt per 5 gallons, and maintaining that for 2 weeks. One of the problems with ich is that it has a complex life cycle and treating the entire tank is essential to prevent re-infection.
There have been a couple of good responses in
the other thread where we were talking about this situation. I enlisted the help of a couple of people that I have great respect for and they came through yet again.
I was leaning towards either injury or a bacterial infection, and Lotus and Purple seem to be heading that way, too. This post reinforces that idea. I think what is going on is that the original fairly large flat white spots were the result of an injury that could have happened anywhere, including when they were netted at the store (that's not uncommon). The whitish coloration could have been signs of a bacterial infection starting, but injuries often just look like white areas because the scales that contain the pigments are damaged or missing. I think the white protrusion you see coming from the original spots is the first sign of a secondary fungal infection. This is also quite common.
There are several products available that tackle both bacterial and fungal infections. I have heard good things about
Junle Labs Fungus Clear. Others probably have better first-hand knowledge than I. Don't hesitate to PM me (or others) if we can be of further assistance.