Wow, ton of work. LOL on missing fish, do you have a dog or cat? If you don't see good results you may also want to get to bare bottom since HT parasite treatments are usually described as requiring such for frequent siphoning (so the Ich don't have a haven during their non-host stages). Many fish live for years in sterile tanks, so a few months will be no fun but won't hurt 'em as bad as Ich.