I think FlyDan solved the mystery! I can't imagine adding anything (except supplements) to my tanks for any reason! I just don't think they're indicated in the marine setup, though they can work well in FW. (an exception might be Copper in a QT for external parasites.) But I imsagine I would try almost anything if I awoke to see my tank in pain!
CMom, maybe you'd like to clean the tank and get some FW hardies, fancy goldfish, a lizard, or a terrarium of tropical plants. Your name says 'mom' so not only are you busy but your kids don't care if they have exotic SW fish or bright, chubby, fancy goldfish. Both types are happy to see you approach the tank at feeding time.
Marine aquaria is not for everyone; when the effort outweighs the pleasure, it might be time for a change. I may be fairly successful at SW aquaria, but there are a lot of things I'm not proficient at and don't care to becomes so. Some things I have to try before I know if I like them, regardless of success or failure. So don't worry that you might have "failed." It sounds that you put some time and $ into this project in order to have things work. Like having LR and a skimmer. Also know that if you do decide to try something else, there is a pretty good market on ---- for used equipment, especially things like skimmers. Like jewelry and musical instuments, marine aquaria accessories tend to retain their value.
<MY TAKE ON THE DSB>
DSB is the way to go! I like what the LFS guy said: '...gasses will get trapped in the sand or cc, the water will be testing fine and you will wake up one morning and all of you fish will be dead...' Sure, if you do something dumb like vacuum the substrate and stir all those gasses up! Substrate IMO is necessary to harbor scavengers, those 'gases' mentioned above (they are from bacteria that actually eat nitrates the endpoint of the traditional "cycle" and only live in areas deprived of Oxygen,) to give a "natural" look, and to make the fish almost believe they're still in the wild! Did I mention a home for scavengers?
Isn't it amazing how quickly this hobby is evolving?
The cool part is that it is also getting SIMPLER! It takes more planning on the front end, but it really is easier and more spectacular. I could keep my Picasso in a subtrate-free tank without too much trouble. But I have the Picasso AND a whole nighttime WORLD living on my LR that is a spectacular reward that I didn't even know existed when I started!
DSB, lots of circulation, and tons of LR are an asset to any system. Whether you want to keep corals, fish, Octopi or Lobsters. (Even seahorses, but powerdown during the day.)
YBYW >>{{{~}}">