Without knowing anything about your setup and equipment you use the best advice will be general good husbandry methods. It's always rough having someone else watch your tank. Because no one is going to do it exactly like you do, especially if it's someone thats not in the hobby and the only thing they see is a glass box of water. Hard to say what happened to your tank this time though. Has anything died prior to the "crash"? Any new additions? Parameters when it started? It sounds like you have had a lot of die off in the last couple of days, make sure you get all of the dead corals and livestock out so they don't continue to foul your tank.