Hello all! I was wondering if anyone could provide insight as to why my betta tank is getting so dirty so quickly. I do a 25% water change weekly and that includes a gravel vacuum being used. However, the tanks (I have two), are getting so nasty so quickly. Even if I do a complete tank cleaning in a couple of days it will look like this again. The filter cartridge is also getting nasty but even when I change them it doesn't seem to help for long.