Just updating this thread to document that I successfully used this product to rid my tank of a budding Dictyota population--a blue morph and a brown morph. I did NOT remove carbon, skimmer, or GFO during the treatment. Should state that GFO was started at the same time I started treatment as I took my ARID offline.
Took four weeks to completely eradicate and seemed to start working immediately. Don't think it really killed the algae, but weakened/destroyed the holdfasts. The day after the first treatment I noticed pieces of Dictyota floating around the tank and going into the sump. Pieces were then caught by the filter pad I have before the return chamber (don't use the stock reefer filter socks, instead cut a piece of filter pad that I lay on the bubble trap and replace weekly).
Not sure if the pieces broke off on their own or were the work of the blue tuxedo, who kept collecting more for his camouflage, or the sally lightfoot feeding. There were no adverse side effects in corals or inverts. However, every time I dosed, the urchin would release from the surface he was on. He would immediately right himself then go about his business.
Dosed 10ml every three days for four weeks. Total water volume of 100gal, give or take.