Biorb Airstone (suitable for all Biorb Aquariums) 1 pack, 3packs or 5 packs ---The air stone at the base of the aquarium breaks up the flow of air into the aquarium into a mass of bubbles. ---After a time the air stone can become blocked by calcification, especially in hard water areas, reducing the flow of air into the aquarium. ---Replacing the air stone every few months (soft water areas every 6 months, more frequent in hard water areas) will keep your aquarium bubbling away nicely.
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