Yes, I mixed the powder into a small cup of RO water and dumped in. No livestock looked any different during treatment, fish or coral. If you've ruled out any other issues this might be worth a try. Be advised that it will knock back all kinds of bacteria within your tank, good or bad. In my circumstance I was confident that the bad bacterias were outcompeting any beneficial types, as I observed what I believed were infections coupled with progressive cyano for several weeks before treatment.
Collecting about 5gal of skimmate afterwards is essentially a very small water change. You will need to add fresh saltwater back in. The chemiclean is highly reactive within the skimmer and skimming it out is the easiest most effective way of removing it. Carbon doesn't seem to be as effective, but I added some to hopefully polish anything that the skimmer missed.