I thought I would chime in here because I have some experience with AEFW on the large scale. I work for a store that has good practices for quarantining new corals and they still sometimes make it through. All corals are dipped in Coralrx pro for a minimum of 10 minutes and inspected closely for eggs. If I see eggs I scrape them off with a dental tool. I add a relitivley strong powerhead to the dip container and just before I'm about to move the dipped coral to the rinse I blast it with the powerhead. From my experience if you have AEFW dipping every 3-4 days for 3 months is the only way to rid them completely. The gestation period for eggs to hatch is a minimum of 14 days and live flatworms can live for months given a steady food source, reproducing very quickly. AEFW without a food source can only survive about 5 days. With that said, if Flatworm Stop actually works it could be a great preventitive. There definitley are some acros that dont like dips like Turakis, echinatas, and some deepwaters and you may have to dip for less time and dip more frequently if you are qting. Dipping every 3-4 days is key as you are trying to kill them before they have a chance to lay more eggs. Just my 2 cents. Hope it helps.