The Hydro Sponge Filters are better than any sponge filter I’ve ever owned. It picks up waste very well in my hospital (fresh and saltwater) and breeder tanks. It also creates a good amount of water disturbance and provide lots of oxygen for the fish.
While some say the sponge should be replace every 6 months, I don’t replace it at all. I actually don’t see why it should be replaced. I just rince it once a week.