u need to know all your water tested result...as Jimbo said, they just want to make sales and all they said will be 'perfect'...or the more u ask, the more things to buy....its happen in front of me where students want to start marine tank without any research or reading, where the
LFS told him to buy unnecessary goods...read, read and read then ask questions....
if your ich problem already critical,
IMO QT is the best method....