No reason why you need to use bleach or vinegar on a new tank. A simple rinse, plus a thorough wipe down with paper towels, would suffice.
As a suggestion, document your discus delivery in case there's a problem. If it's coming via air, take pix of the container, the fish in the bag, bags floating in the tank, fish in the tank, 12 - 24 hours later, etc. If you run into a problem, having documentation would substantially back up your claims. Even with successful shipments, showing the condition of the box, packaging, any leaks, water temperature, etc., to the shipper is always appreciated.
What are the dimensions of an X 80g tank?