I have a 36 gallon reef tank. I have several snails and hermits in my tank. My tank has been setup for about 5 months now. I now have approximately 45lbs of live rock in the tank. Over the past 2 weeks, I have lost 2 hermit crabs and now a snail. Is this something I should be concerned with? And what should I look at to fix a potential problem? I am new to the saltwater world. All corals and fish seem to be doing fine.