What pallets are using?
I soak a mixture of ocean nutrition formula 1, formula 2 and 2 sizes of spectrum, fish eggs(ebiko).... soaked them in lots of garlic amino acids and vitamins..... that's my magic potion....the fish love them!
As long as the fish is eating well and active.... continue to keep them that way till their immune system actually rid the manifestation of ich.
I had a naso tang and an Achilles tang filled with hundreds of white spots......it slowly went away over 2-3 weeks... be patient and make sure the fishes are feeding well and active. Now, they're both spotless