I have cycled my tank and now have a few fish in the tank and have read so much about bacteria building up in the filter and was wondering what happenend when u change the thin sponge the filter is a internal jewel one
Hey all
I have just bought a second hand jewel corner tank and has a filter hung in the back corner and looking at the media in it.there is a white sock with something in it sitting on black media and was just wondering what it was and if it need to be replaced with new stuff