I have a 2.5 gallon Mini Bow that I've had for about a week and a half and Monday I noticed that the filter was overflowing. The water wasn't filtering through the media cartridge and the unfiltered water was overflowing into the tank. I tried cleaning the cartridge but it continued to happen so I thought it was a bad cartridge and replaced with a new one.
Everything worked fine yesterday but when I checked my tank this morning, it was doing the exact same thing. The new cartridge has only been in there for about 24 hours so I now it can't be a bad cartridge. Is there anything I can do to fix this or will I have to buy a new filter. Also, is it bad for my betta having the unfiltered water flowing back into the tank?