I have had saltwater tanks for many years and got out of the "habit" for a little while. I have only had a 40 gallon with a 20 gallon sump. I just purchased a 55 gallon octagon tank that had been used for freshwater fish. WHat is the best way to clean it and get it ready for a reef tank? I planned on using a razor to scrape off the inside of the glass and use aquarium safe silicone to reseal (it does not leak but is discolored). Next week I am buying a 100 gallon tank with a 55 gallon sump that used to be saltwater. THis tank is amazing, And I am only paying $300 for it. What is the safest way to clean it as it has not been running for about 6 months. Any and all advice would be appreciated.