---
title: "PAR (Photosynthetically Active Radiation) Sensors | Aethair"
description: "Photosynthetically active radiation (PAR) is the light band plants and algae use for photosynthesis, in µmol/s/m². See which sondes report it underwater."
url: https://aethair.io/parameters/par/
---

Measurements · Radiation & Light

# PAR (Photosynthetically Active Radiation)

Photosynthetically active radiation (PAR) is the light in the band that plants and algae use for photosynthesis, reported in µmol/s/m².

[Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure PAR (Photosynthetically Active Radiation) Monitoring](https://aethair.io/build/?params=par)

At a glance

µmol/s/m² Radiation & Light

1 way to measure it

- **Thiamis** 1 external instrument

What it is

## What is PAR?

Photosynthetically active radiation (PAR) is the light in the band that plants and algae use for photosynthesis, reported in µmol/s/m². On this platform it is an underwater light reading from a multiparameter water-quality sonde, and it has one source: the [YSI 6-Series](https://aethair.io/sensors/ysi-water-quality-sondes/) sondes, which can carry a PAR sensor among their channels.

The 6-Series covers YSI's large and mid-size sondes (the 6600, 6600EDS, 6920, and 6820) and the compact 600-series. All are now discontinued by YSI (the 6600 is succeeded by the EXO2 and the 6920 by the EXO3), so on the platform PAR mostly serves existing deployments.

How it is measured

## How PAR (Photosynthetically Active Radiation) Is Measured

A 6-Series sonde connects to a [Thiamis](https://aethair.io/products/thiamis/) gateway over SDI-12. Its response is an ordered list of values with no labels, so the sensor order configured in YSI's software when the sonde is prepared determines which value is PAR. A deployment reports PAR only when it was set up with that sensor.

Another sonde family in the sensor catalog, the Eureka Manta, also offers a PAR sensor, but the platform's Manta driver cannot read it, so PAR from a Manta does not reach the platform.

An instrument on Thiamis 1

A third-party instrument connected to a Thiamis gateway, reporting into the same Environet account.

### Every device and option that measures PAR (Photosynthetically Active Radiation) 1

| Device / option | Type | Base platform | Measures |
| - | - | - | - |
| [YSI](https://aethair.io/sensors/ysi-water-quality-sondes/) · 6600 V2, 6600EDS V2, 6920 V2… | Water Quality Sondes | Thiamis | PAR (Photosynthetically Active Radiation) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Chloride](https://aethair.io/parameters/chloride/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Conductivity](https://aethair.io/parameters/conductivity/) |

[Configure PAR (Photosynthetically Active Radiation) Monitoring](https://aethair.io/build/?params=par)

Related

## More in Radiation & Light

[Solar / Global Radiation](https://aethair.io/parameters/solar_radiation/) [UV Index](https://aethair.io/parameters/uv/) [Radon](https://aethair.io/parameters/radon/) [Illuminance / Light](https://aethair.io/parameters/light/)

Questions

## PAR (Photosynthetically Active Radiation) FAQ

Which instrument reports PAR on the platform?

The YSI 6-Series multiparameter sondes, over SDI-12, when the sonde is configured with a PAR sensor.

Can I read PAR from a Eureka Manta?

No. The Manta offers a PAR sensor, but the platform's Manta driver has no entry for it, so its column is ignored.

What unit is PAR reported in?

µmol/s/m².