One is metal… one is plastic… u want the plastic. Used to be very common yrs ago and they were dirt cheap. These days its around the same price as buying regular bio balls in bulk. I would suggest against the metal. They will most likely rust and break down over timeThen how is the above different from this one
7.2.8. Pot Scrubbers
One of the best aquarium filter media turns out to be plastic pot scrubbers.aquariumscience.org
Then how is the above different from this one
7.2.8. Pot Scrubbers
One of the best aquarium filter media turns out to be plastic pot scrubbers.aquariumscience.org