Nudis!

[theSickness]

If I used flatworm exit in a tank why would I have to dose twice if I do not perform a water change? Wouldn't the chemical be present constantly to wipe out the hatchlings?

 

[organism]

Because you don't wanna leave that stuff floating around the tank, and I think it degrades and dissipates over time. Always do water changes when treating your tank with additives for pests.

 

[mfinn]

When I treated my 40 gallon zoanthid tank with FWE, I did not do a water change for 3 days. Then 7 days later I did another treatment, waited a couple days before doing a water change.
Yes you should treat the tank atleast twice.