How did the treatment go?
I had flatworms in the tank from a few early pieces that I wasn't careful about dipping/treating. They managed to multiply in the past couple weeks, even with a significantly reduced feeding regimen and weekly 30% water changes. I manually siphoned them out several times, and thought I had caused a dent in their population. Today I made up my mind to finally use the Flatworm Exit purchased several months ago. There were at least 5x the population of flatworms I expected that were not visible.
Started out with the recommended dosage, and after half an hour when there were still unaffected planaria, added another dose (for a total of a double dose). About an hour after treatment began, my fish began flashing against the sandbed, so I put in a large bag of fresh carbon and monitored the inhabitants for a couple hours. Cerith snails fell over initially, but began to recover about 6-8 hours after treatment. There were still about 8-10 resilient flatworm buggers still on the glass that I had to manually suction out. I had a 30% water change on hand that was not used.
Normally I would not medicate in any form within the DT, but I've had planaria problems with freshwater shrimp tanks that required the use of fenbendazole (an active ingredient in canine dewormer) to eradicate. Decreasing feedings and aggressive filtration isn't enough. It's possible another FWE treatment will be in order in the near future, and I still have some, but given how pricey it is compared to fenbendazole, I'm thinking I want to grab the next flatworms I see and see how effective fenbendazole is against them.