What is this stuff??

[penguinfish]

Well...I've been keeping fish for a long time but have never really worried about this...but I think maybe I should. Everytime I switch off my filter for a while and then turn it back on, all this muck comes out of the filter hole and basically pollutes the whole tank. I don't think it causes any harm to the fish but maybe it does. I tried opening the filter media and there was the muck in the bottom layer of my filter media. I think it may be the dirty particles that the filter has sucked up. But I'm not 100% sure. Does anyone know?? :huh:

 

[redstar8]

why are you switching the filter off?

 

[Dangerdoll]

I agree with that, the filter shouldn't ever be turned off for a little while periodically.

 

[hurricanejedi]

Filter gunk is pretty normal too.

 

[TKOS]

That is the stuff that filters filter out. The gunk in the water. It is small normally but accumulates and joins together. The same stuff will come out of the gravel when use a gravel vacuum. You should be cleaning it out of the filter periodically. Rinse out old filter media.