Well, it's not enough for that guarantee you really want! :p Why would you treat with ParaGuard after a hyposalinity treatment?

I had ich in my tank too, I think it came in with one of my tangs, anyway my vlamingi and regal tang both got it. My response was to buy a few more cleaner shrimp and use garlic. The regal tang would actually hang out by the shrimp and over a couple of weeks it disappeared. I don't like copper and thanks to the shrimp didn't have to try hyposalinity.

Just to make sure if there was any surviving kist, the larvaes would die if they ever got out of it while I was raising the salinity, so that they would not attach to the fish.

You could have avoided the chemical treatment simply by leaving them in hypo for a couple more weeks. Personally, the only chemical I use on any regularity is Praziquantel (wormer), and is more important than Ich treatment imo.

Well he's in the display for 2 days and no sign of ich yet. I don't know how long I should wait until I know for sure ich is gone? I could not do longer hypo treatment because I am returning to work and won't have time to monitor all this.

prazi might be more important one some fish but if a fish is dying of ich, prazi won't do any good.

I suppose you have to wait forever...? :p With fish like Hippos I really don't think you're ever totally safe unless it's a FOWLR and you hypo the whole tank, and never add another thing to the tank.

I have never had a saltwater fish die from Ich, but I have had several die from worms. I dissect all dead fish. Sometimes I can tell what happened, sometimes I can't. A kid's microscope comes in handy.

EDIT: I don't think you actually said what kind of fish you were quarantining...?

Same as in this threat, the little ich magnet hippo tang and one clown fish.

The hippo has great appetite and I am feeding him garlic soaked food right now. He's been in the DT for 3 days and no ich. I guess if he's still ok in about a week I can assume he'll be ok unless I introduce something bad.

You never had a fish died from ich but I have read of many fish dying from this parasite. It can be quite serious sometimes.

Well, hopefully it works for you.