Aqua One - Golf Ball Airstone Ceramic Ceramic vs Sand Based Airstones Ceramic = Produces a steady stream of very fine, tiny bubbles that make very little noise. Sand = Makes larger, coarser bubbles that often pop with more surface splashing and sound. The most common air stone used in hydroponics is the 'Golf Ball Airstone' Roughly 50mm in diameter - the golf ball air stone is suitable for most situations Can be attached with 4mm or 6mm tubing, with the special dual inlet connector Provides ample oxygen and water movement Releases a constant stream of fine small bubbles Intended to be used with an air pump, check valve and airline tubing