Removing antibiotics in QT without removing copper

[Quarryshark]

I’m current treating a Heni and a Watchman Goby in QT and have CP at full strength at 1.75 ppm. Due to the Heni getting a bad case of popeye, I was forced to dose erithromycin with the CP. The eye is clearing up nicely and I plan on finishing the antibiotic treatment. The problem is that the instructions say to do a 20% water change and to run carbon to remove the medication. Unfortunately this would also remove the copper I’m quite sure. What would my best course of action be to remove the erithromycin? I don’t think carbon is good option. Perhaps a series of water changes with predosed CP, or just leave the erithromycin in? I have 3 more weeks of copper treatment to go. Tia.

 

[AcroNem]

I would do a water change with water that is matched with the quarantine system water. Carbon is going to take them both out. I don't know 100% with erythromycin how long it would stay active in your system or if it could cause any more harm if you left it in.

 

[andrewey]

I'm not aware of any reliable means of removing the erithromycin without removing the copper. In case you hadn't seen it, you might want to check out this post by @Humblefish - it's a pretty succinct explanation of some of the challenges of using antibiotics in tandem with copper and has some suggestions for their administration.

https://www.reef2reef.com/threads/the-bacterial-infection-predicament.310311/

 

[Quarryshark]

Thanks all and I agree. Can’t really remove one without the other and carbon would be the least controllable method. Here’s what I’ll do unless someone has a better idea.
After the first round I’ll do a approximate 30% water change and after the second round two to three 30% water changes. The tank is a 29 gallon, 8 gallons per change in two gallon increments. The dosage for CP for a 1.75 concentration per this chart is 1.04 ml per gallon.
https://www.reef2reef.com/threads/ratios-for-dosing-copper-power.385871/Thus for each 2 gallons put back in, I’ll dose the bucket with 2.08 ml of copper powered and check with the Hanna about a half our later, making any needed adjustments. This should keep the copper level steady and hopefully dilute the erithromycin sufficiently. @andrewey, thank you for the link.