How effective is a sponge filter without the air pump?
A sponge filter is no use without an air pump as you need the pump to force the water through the sponge to remove the impurities. If your pump fails to work, dismantle it, you will find a rubber diaphragm and a hole where the air comes through, this very often gets blocked with gunge, clear it out using a cocktail stick if necessary and you should find it will work again. This happened with my daughters pump and when i took it to pieces i couldn’t believe the gunge blocking the pump up.
