1.75 PPM copper power, Hanna copper checker. Use metroplex as well.
For eels I would use CP.
@HotRocks just got a giant golden puffer through copper no problem though. Some eels can handle it. TTM doesn’t treat velvet so I would be nervous using it and assuming the dish are safe. With anthias you’ll want to add the metroplex for sure as it’ll treat brook and uronema.
https://www.reef2reef.com/threads/my-current-qt-process.483371/
Use metroplex instead or in addition to spectrogram.
Be careful with CP that you don’t have any poly in the filter as it’ll remove the meds. Keep in observation with other fish afterward to make sure it worked as CP has been shaky.
If you wish to try copper, I have gotten some eels through.
A bigger concern I have though is mandarins and small fish with eels. Mandarins are slow and easy prey for eels, I don’t recommend this pairing at all :/