---
title: "What are nanobubbles and what do they do | Alchemal"
url: "https://alchemal.com/technology/nanobubbles/"
description: "Nanobubbles are oxygen bubbles small enough to stay suspended for weeks, so oxygen reaches the whole water column instead of just the surface."
source: "Alchemal — alchemal.com"
---
# What a nanobubble is, and why it matters to your pond

Nanobubbles are oxygen bubbles roughly 2,500 times smaller than a grain of salt. Bubbles that small are neutrally buoyant: they don't rise and burst. They stay suspended for weeks, releasing oxygen through the whole water column, including the deep water and the sediment interface, where low oxygen sets the table for algae, odor, and fish loss.

## Why the bottom matters more than the top

Nearly every problem on our [problems index](https://alchemal.com/problems/) begins at depth: warm water stratifies, the bottom layer runs out of oxygen, and the sediment starts releasing the nutrients stored in it. Surface equipment can't reach that layer. Suspended nanobubbles can, which is why the same mechanism addresses [algae](https://alchemal.com/problems/pond-algae/), odor, and oxygen crashes.

*Summer stratification: a warm, oxygen-rich surface layer sits over a cold, oxygen-poor bottom. Illustration, not to scale.*

## What counts as a nanobubble

"Nanobubble" is the word buyers search, but it is not the word the standards use. The international fine-bubble standards, written by ISO technical committee 281, define a fine bubble as one 100 micrometres across or smaller, where a micrometre is a thousandth of a millimetre, and an ultrafine bubble as one micrometre or smaller ([ISO 20480-1:2017](https://www.iso.org/obp/ui/#iso:std:iso:20480:-1:ed-1:v1:en)). The committee writes "ultrafine bubble" rather than "nanobubble," because the physics does not change at any single line on the scale, and measured ultrafine bubbles in water tend to sit between about 100 and 200 nanometres. We use "nanobubble" because that is what the field and the search box call it, and we mean the ultrafine bubble the standards describe.

## What nanobubbles can't do

They are not a herbicide, and they are not an emergency response to a toxic bloom. They also won't fix clay turbidity or external nutrient dumping. Where the mechanism doesn't apply, we say so. Each problem page carries a "when this isn't the right fix" section for exactly that reason.

## What the published work shows

The mechanism is not ours, and neither is the evidence for it. Independent bench work has measured how much oxygen nanobubbles actually move into water: in one clean-water comparison, micro-nano bubble aeration roughly doubled the standard oxygen-transfer efficiency of conventional aeration under the same conditions.

In a bench-scale comparison, micro-nano bubble aeration roughly doubled standard oxygen-transfer efficiency against conventional aeration under the same conditions, reaching about 54% at its best operating point.

[Kizhisseri, Sakr, Maraqa and Mohamed, *Heliyon*, 2025](https://doi.org/10.1016/j.heliyon.2025.e41687)

A 25 L bench test in clean water. It shows the mechanism's headroom, not what any installed unit delivers to a real pond.

## The same mechanism, measured across the water world

The reason nanobubbles matter to a pond is the reason they are being studied in greenhouses, hatcheries, and treatment plants: oxygen carried through the whole water column, to the places the problem forms. These are published trials of the mechanism, not Alchemal results.

6-25%

In published trials, seeds started in nanobubble water germinated 6 to 25 percent more often, and oxygen and nitrogen nanobubbles raised stem length, stem diameter, and leaf growth.

[Ahmed et al., *Journal of Agricultural and Food Chemistry*, 2018](https://doi.org/10.1021/acs.jafc.8b00333)

Lettuce, carrot, fava bean, and tomato in tap water. Air nanobubbles alone did not raise germination. A bench study of the mechanism, not a field or Alchemal result.

2×

In a controlled shrimp trial, nanobubble aeration roughly doubled total harvest and productivity against a conventional diffuser aerator, and survival reached 95 percent.

[Rahmawati et al., *Aquaculture and Fisheries*, 2021](https://doi.org/10.1016/j.aaf.2020.03.005)

Pacific white shrimp (Penaeus vannamei) in 50 m² indoor raceway ponds over 81 days, nanobubble versus diffuser aeration. A controlled trial, not an Alchemal installation.

95%

In a pilot reactor, nanobubble aeration reached 95 percent removal of organic load against 80 percent for a fine-bubble system, and lifted nitrogen removal to 99 percent.

[Ahmadi et al., *Frontiers in Energy Research*, 2022](https://doi.org/10.3389/fenrg.2022.884353)

A sequence-batch-reactor pilot at a 400 mg/L organic load and 15-day retention, nanobubble versus fine-bubble aeration. A pilot result, not an Alchemal installation.

These findings describe nanobubble oxygenation as a mechanism, not an Alchemal unit. Our own installations publish their records as case files as they go in. The measurement side is documented in [how we measure](https://alchemal.com/technology/how-we-measure/).

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