Marina Round Air Stone

A small spherical stone is the least fussy way to add gentle circulation to a nano tank, a quarantine bin or a fry tub, where a large diffuser would simply be too much water movement.

Key features

• The compact ball shape hides behind a plant or ornament and takes up almost no floor space.
• Modest air demand, so it runs happily from a small pump or from one branch of a shared manifold.
• Two diameters are offered; the size selector shows what is currently in stock.
• Fits standard airline tubing, so nothing special is needed to connect it.

Worth knowing: most of the oxygen exchange comes from the ripples the bubbles make when they reach the surface, not from the bubbles dissolving on the way up. Aim for a stone that keeps the top of the water moving rather than the biggest bubble column you can manage. Stones clog with scale and biofilm over time and are meant to be replaced. Pumps, tubing and valves are all in Aeration.