@scott11106 never implied you were doing everything wrong. They never implied you were doing anything wrong at all. They never implied you weren't trying. All that they said is that salt is not as forgiving, which is absolutely true. It's possible to infer from that statement that you made a mistake, but I personally wouldn't take it that way. Even if you did make a mistake, there's nothing wrong with that. Even the pros make mistakes. At the National Aquarium in Baltimore this weekend, we had an issue where one of the aquarists left the fill valve open on our chiller vats. An entire backup area flooded with dozens of gallons of saltwater. It took forever to clean up. But, that's how aquariums work. It's impossible to know everything, so you're going to make mistakes. Even when you know a lot, you're still going to make mistakes.
Having said all that, this sounds like a bacterial bloom of some kind. Dosing organic carbon will not help. How did you start this tank? What kind of rock did you use? Did you add an ammonia source?