Am I doing this right? Setting up a QT

[Humblefish]

The thing with ich is. Even if you go the full 72 days it can come back. It's caused by stress and you can get it even if you run fishless for 500 days.

Ich doesn't just appear out of thin air. It is a ciliated, protozoan parasite which can only be introduced into an aquarium one of three ways:

1. An infected fish (Trophont or attached stage)
2. Coral/invert (Tomont or encysted stage)
3. Water (Theront or free swimming stage) - usually occurs via cross contamination

Currently, the longest known time it took for all the theronts to be released from a group of tomonts is 72 days. If a theront does not find a (fish) host to feed upon within 48 hrs it will starve to death and die. Thus ending the parasite's life cycle & presence in your tank. So, the only way going fallow for 76 days (4 extra days to account for ich's other life stages) can fail is if you were to encounter an undiscovered strain of ich which took longer than 72 days for all the theronts to be released from their tomonts. Or you cross contaminated the DT (from the QT) whilst going fallow.

I agree stress is not good for any fish and it can cause problems. But it can't cause any disease to manifest unless it is already present in your aquarium.