About a year ago my heater broke in my 30 gallon SW tank. It never shut off. I arrived home from work and I can't remember what the temperature was but I had to use a meat thermometer to get a reading. Every thing was dead or so I thought. Immediately I started water changes of 5 gallons at a time until I got the temperature down. As I was cleaning out everything I noticed my clown was still hanging on. I left it in the tank cause I thought it was the only thing that made it. I found out that a few hermit crabs were still roaming around. I did not do anything other than start regular water changes. I started out with 5 gallons a day and went to 5 every other day and ended up at 10 a week. Today I do 10 gallons every other week. When I did the water changes I would vac the sand bed. In the beginning the rock looked bad, brown and dried out looking. The tank smelled but as time progressed the rock began to get its color back and the smell went away. I decided to add some snails to help with the sand(they are the ones that go under the sand and a tube is sticking out of the sand). The only thing that really seemed bad was algae. I figured it was a by product of the heater problem. I would scrape and remove it. I then added Astraea Turbo Snail and they cleaned up the rest of the algae. I also added another clown and it seems fine. My rock still just does not look as good as it did before. The colors are not as vibrant. I moved the tank and really gave it a good cleaning and noticed it had a lot of the dried look on the bottom and it left a large amount of sediment under the rock. I am wondering if everything is OK or has the rock been destroyed and needs to be replaced. As far as the inhabitants of the tank they are in great spirits. Any thoughts?