# Air stone

> An air stone is a porous diffuser connected to an air pump that breaks air into fine bubbles in a nutrient solution, mixing it and helping maintain dissolved oxygen.

- Canonical: https://genetixbay.com/knowledge/glossary/air-stone.html
- Also written: airstone, air stones, bubbler, air diffuser, diffuser stone, air pump and stone
- Glossary category: Systems and media · Evidence: Established
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

An air stone is a porous block or disc, made of mineral, ceramic or sintered material, fed by an air pump through tubing. Air forced through it emerges as many fine bubbles. The bubbles themselves add some oxygen, but their main effect is circulation: they keep the solution moving, bring water to the surface where it exchanges gases with the air, and prevent stagnant zones.

## In practice

In [DWC](https://genetixbay.com/knowledge/glossary/dwc.md) and [RDWC](https://genetixbay.com/knowledge/glossary/rdwc.md), air stones run 24 hours a day. A rough rule many growers use is about 1 L/min of air per 4 L of solution, or more. Clean or replace stones when bubbles become coarse or uneven, since mineral and biofilm build-up clogs them. Place the pump above the water line, or fit a check valve, so water can't siphon back into the pump if it stops.

Aeration only works well in cool water; warm solution can't hold much oxygen however hard it is bubbled.

## Don't confuse with

- **Water pump**: moves solution; an air pump moves air.
- **Venturi or oxygen injector**: other ways of raising dissolved oxygen.

## Related terms

[Dissolved oxygen](https://genetixbay.com/knowledge/glossary/dissolved-oxygen.md), [DWC](https://genetixbay.com/knowledge/glossary/dwc.md), [RDWC](https://genetixbay.com/knowledge/glossary/rdwc.md), [Reservoir](https://genetixbay.com/knowledge/glossary/reservoir.md), [Chiller](https://genetixbay.com/knowledge/glossary/chiller.md)

## Read more

- [Deep water culture (DWC)](https://genetixbay.com/knowledge/systems/dwc.md)

## Sources

1. Resh HM, 2022. Hydroponic Food Production, 8th ed. CRC Press. https://doi.org/10.1201/9781003133254