IMO I would suggest simply getting rid of the LSB, taking out all the rock and soak it in 250ml of bleach for a few days. Then restart with your new non-living rock, add some new sand and a way you go. You might have to wait longer for everything to cycle-but that's what you would have to do IMO.
Heating up a 72gl tank to 93 will do little or nothing at all. I can tell you this because I have seen my roomates 60gl tank heat up to 94 for a total of about 10 days last month, and guess what-he suffered no losses, just an increase in algae
cheers, Rich