The fish which i want to purchase costs 2 grand and it will be placed in this tank, alone[/QUOTE]
Hello; I would clean the tank and it's equipment with something like Clorox and start over. If you have some bb available to jump start then back in business soon.
Hello; If I had another disease/parasite free tank from which to seed the bb and jump start a cycle, then I would sterilize the tank in question with all the equipment and start over. For a two grand fish I would anyway, might not for a $1,995 fish. (humor)(???)
While I am not absolutely sure that a Clorox solution will do the trick, that is where I would put my efforts. I have done so on a few tanks and the tank can be back in operation fairly soon. The tricks are to rinse everything well, have some prime/safe around the treat the Clorox residue in the new setup and have some bb loaded material so the cycle can be jumpstarted.