I made the switch from a 55 to a 90 gal
a couple years ago. Plan ahead to make the switch fast and easy. Be sure to have enough new water to make up the difference. I broke the 55 down and transferred all inverts and fish over to a 20 gal
quarantine tank using water from the 55. Save as much original water and substrate as you can. This along with your lr
will prevent another cycle. I setup the 90 with the water, substrate and lr
and let the tank circulate for a week or so. I kept a check on the ammonia, nitrite and nitrate and did not see a cycle. Then I just acclimated the fish over to the 90. I did not have any losses.
I would think a "smoked" tank could just be cleaned. Be careful if you suspect it has been around the heat from the fire. This could be nothing but bad.