Medifin killed my filter?

[Magzire]

After a 3 long day romp (spawning) most of the goldfish damaged their slim coat. They developed white fungus along their side. I gave them a salt bath and dosed the pond with Medifin twice in one week. Doing much better now
However i notice when I was cleaning the filter floss yesterday (2 weeks after adding Medifin) it had a rotton egg smell. First time this has happened.

I'm guessing it's caused by Medifin. Now I am worried it wiped out my beneficial bacteria on the bio media.

 

[Meyer Jordan]

Did you strictly follow the dosing instructions?
Medifin contains Malachite Green which is a broad spectrum anti-bacterial and anti-parasitic.

 

[Magzire]

I guess not

Even if the beneficial bacteria was wiped? It will recover, right?

I just have a feeling I have bad bacteria. Any tips to boost filter?

 

[Meyer Jordan]

+Some viable bacteria may remain and they will re-colonize the filter. Of greater concern is the beneficial bacteria that populated the biofilm on all of the pond's submerged surfaces. This was probably affected also.
Not much you can do other than monitor the Ammonia level and have some Prime on hand.
I hate pond water treatments!!!!

 

[Meyer Jordan]

Did you filter the water post-treatment with AC or do water changes? If not you need to as this chemical does not go away quickly and requires removal from the water. Ideally this chemical/treatment should only be used in a quarantine tank.