I am sure there is some sensitive organisms that will not appreciate temperatures outside of 76-84. If you are concerned about the live rock and want to eliminate the ich, wait six weeks without any fish and then start a hospital tank and add slowly. I personally do not think high temperatures (85-92) would permanently damage your live rock. Some reefs in the wild can get this warm. However, I think the safest thing to do would be to run the tank empty for six weeks in a normal temperature range.
:joy: