i completly agree with Zimmanski, Raising the temp speeds up the life cycle of ich, the colder the tank the slower the life cycle, some people disagree with doing this with coldwater fish but everone has there own way of doing things, Correct me if im wrong but the huge water changes and the complete replacement of filter media is far more trawmatic for the fish, ammonia levels wud rise, ph wud alter, ect. new tank syndrome all over again.
U just needed to treat the tank with white spot remover remove the activated carbon in you filter, and follow the instructions. after 48 hrs 25% water change, repeat treatment, and do this over for 14 days. The advice of APi white spot remover has always helped my fish they have helpline number aswell. But take the advice of Zimmanski pick a treatment and stick to it.