Quarantine metronidazole dosing regiment

[Reef Pro]

@Humblefish I know you recommend copper power and metronidazole at 25 mg per gallon when quarantining. what are the procedures when dosing metronidazole? Is it a one time dose or does it have to be dosed frequently to keep potent in the water?
In addition, what drug would you recommend to treat a scopes tang with cloudy eye?
Also what are your thoughts on Nitrofurazone? Worth dosing with the copper power and metronidazole?

I originally started dosing my quarantine with cupramine prior to reading your procedure and recommendations with copper power... I have a reactor running with carbon to remove the cupramine however it seems that its not removing it.... still at a level of .05 from my Hanna checker.... any thoughts??

Thanks in advance ! Very much appreciated!