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 will keep your aquarium bubbling away nicely.
User Comments about the biOrb Airstone - 2 pack
I love my Biorb tanks, but the parts and filter packs are wayyyoverpriced. The 8 bucks shipping was ridiculous for two foam aristones that weighed less than an ounce and cost 6 bucks. I now adapt readilyavailable off the shelf foam air diffusers with some tubing pieces and they only cost about 2 dollars for a four pack.