Some help for a friend with a freshwater setup. 60x30cm About a dozen fish, Gravel on the bottom 1 internal Rio powerfilter with a sponge inside!
every time they do a waterchange they scrub the filter under the tap. Now I'm wondering where the bacteria lives? Wouldnt they be better off with an undergravel, & wash the sponge in tankwater?
I'm a saltwater Guru & need advice :-?