Active Aqua Round Air Stone - 4" x 1"

The 4" disc is best suited for compact reservoirs, single-bucket DWC systems, and smaller containers where a larger disc would exceed available floor space or oversize the aeration for the volume. For mid-to-large reservoirs requiring broader horizontal oxygen distribution, the Active Aqua 8" Round Air Stone provides double the disc surface area from the same product family.

Round disc stones distribute bubbles across a wide, flat horizontal surface — providing even floor-level coverage across the reservoir base. A cylindrical air stone produces a focused vertical bubble column, which is more effective in tall, narrow containers like DWC buckets where depth coverage matters more than horizontal spread. For wide, shallow reservoirs or flood trays, the disc format generally delivers better overall oxygenation.

This stone uses a 3/8" diameter inlet — note this is larger than the standard ¼" tubing used by most small air pumps. Confirm your pump and distribution setup uses 3/8" output tubing before ordering, or use a reducer fitting if stepping down from a larger line. Most larger-format air pumps and commercial aeration setups use 3/8" tubing natively.

Yes — an inline check valve between the air pump and the air stone is strongly recommended whenever the pump is positioned at or below the waterline. If power is interrupted, a check valve prevents nutrient solution from back-siphoning through the tubing into the pump body. Check valves for 3/8" tubing are widely available and should be considered standard in any reservoir aeration setup.

Soak the stone in a diluted hydrogen peroxide or citric acid solution between cycles to dissolve mineral deposits and organic buildup that accumulate in the micropores over time. Rinse thoroughly and allow to dry completely before reinstalling. Regular cleaning maintains full bubble output and extends the usable life of the stone — replace when cleaning no longer restores consistent airflow across the full disc surface.

The 8" disc offers four times the surface area of the 4" version, making it the better choice for larger reservoirs where wider horizontal bubble distribution is required. The 4" is the right fit when reservoir floor space is limited, when the container volume doesn't require large-scale oxygenation, or when multiple smaller stones distributed across a large reservoir are preferred over a single large stone. Both use the same 3/8" inlet and suction cup mounting system.