Flat Circular Air Stones Keep your nutrient solution fully oxygenated with an air stone. These flat and circular air stones are great for the bottom of small to medium sized reservoirs. How Flat Circular Air Stones Work The flat circular air stone is a 4 or 6 inch diameter "slab" of porous stone. An inlet nodule is located on the inside of the ring to allow the air stone to be connected to an air pump via a length of air line. When connected to an air pump, the air will exit the air stone through the many pores in the stone. When the air stone is submerged in water or a nutrient solution, the effect is that many small bubbles are produced and released from the surface of the stone. The bubbles create movement in the water or nutrient solution keeping it well mixed. The movement at the surface also greatly increases the amount of oxygen being dissolved into it. Dissolved oxygen discourages anaerobic microbes which can cause root diseases and feeds oxygen to the friendly aerobic microbes. An air stone helps to keep your plant’s roots healthy while also providing oxygen for the roots to absorb. The Flat Circular Air stone will sit flat at the bottom of a tank or reservoir. Adding an air stone to your reservoir really does increase the speed of your plant’s growth and creates a healthier root-system. An air stone is highly recommended for all hydroponic systems. To see our full Air Pumps & Airstones range, click here