Considering restarting 75 gallon tank
I have kept a thriving 75 gallon reef tank for almost 10 years. I had live rock, fish, anemone, shrimp, some corals, hermit crabs and other assorted cleaners. Then, about a year ago, I started getting pretty bad algae. About four months ago, I was in an accident, broke several bones and was laid up, unable to maintain the tank and all my livestock died with the exception of a cleaner shrimp and several hermit crabs. Now, I've re-stabilized it, however, I can't keep damsels alive for more than 12 hours and soft invertebrates(snails, sea hares,etc) literally "crawl out of their shells" and die in 5 minutes or less. At the same time, I still have the cleaner shrimp and several hermit crabs that seem to thrive, but that's all. I've tested for ammonia, nitrates, nitrites, Ph, salinity, and copper, and all those tests(both at home and several stores) have come back fine. I've been trying to re-introduce livestock for close to 2 months now with no success. Considering restarting by either boiling(sterilizing) my substrate and rock or replacing, but if I have to spend another $600 plus to replace all my substrate and rock, I may just give it up.
As long as the problem isn't chemical(as in "toxic metal contamination") would sterilizing get me a good restart?
Any other ideas out there?