Sorry to hear about the fish. I believe this is Aeromonas. Sulaplex will likely be effective against it but better if used with Kanplex or Furan 2. Sometimes it takes this several treatments to clear up and rotating between two treatments is necessary.
So if you have other established tanks with biomedia I'd go ahead and place some of that biomedia or your old biomedia in your filtration and run it in order to remove the ammonia. In my experience neither Kanaplex nor Furan 2 will destroy a healthy biofilter to the point of halting nitrification ... not even close.
How have you been keeping your old media? Does it have an ammonia source?
The stress coat isn't needed. For the most part, it's redundant if you're adding prime and prime is the best conditioner imo.
BTW - What's your tank pH?
So if you have other established tanks with biomedia I'd go ahead and place some of that biomedia or your old biomedia in your filtration and run it in order to remove the ammonia. In my experience neither Kanaplex nor Furan 2 will destroy a healthy biofilter to the point of halting nitrification ... not even close.
How have you been keeping your old media? Does it have an ammonia source?
The stress coat isn't needed. For the most part, it's redundant if you're adding prime and prime is the best conditioner imo.
BTW - What's your tank pH?