To re-locate a sponge filter or not?

[Amelia]

I am going to break down my quarantine tank with a small sponge filter that I want to put in my main tank as it is full of bacteria and in case I need to re-establish another tank. I recently bought 4 Oto’s and the first day added the trio of meds recommended by aquarium coop- ich x, maracyn, paracleanse. Three died within 24 hours and the fourth died five days later. Is the filter ok to put in the main tank or is that a horrible idea? I had previously quarantined four angelfish in there and everything was perfect. Water parameters good. I have no idea what happened to make the Oto’s kick off, very disappointing. Penny for your thoughts peeps and thx for your help 

[FrozenFins]

After every quarintine I just let the sponge filter to dry out. I would suggest to do the same as this will kill of any harmful parasites or bacteria. After its dried out I put it back into my Community Tank where the beneficial bacteria can start colonzing on it for my next quarintine. 

Better to be safe then sorry

[KBOzzie59]

Quarantining is a good thing, I just do not understand the immediate inclusion of the meds (unless you know you are getting dirty fish).  I always have a good look at the store and if the tanks are on a shared system I'll look at several tanks.  Once home I observe for at least 2 weeks and treat as needed.  If I don't see ich I don't treat for ich.  Nothing visible on their exterior I don't treat for that.  No weird swelling, poops looks normal then I don't treat for internal bugs.  

[Amelia]

KBOzzie59- I have had several tanks with sick fish from the store in the past and acted too late, so to be proactive, as Cory says he does with all of his fish , I thought that the med trio would be a worthy approach. The fish looked healthy and the private fish store had had them for about 10 days prior to my purchase