Mini Secchi water observation app

What Mini Secchi measures

The app guides a participant through observations with a physical Mini Secchi disk. The method records water clarity and colour, including colour comparison using the Forel–Ule scale, together with the context required by the project protocol.

Mini Secchi is not a general pollution detector and does not make a phone alone a professional water-quality instrument. What the data can support depends on the protocol, equipment, quality controls and research question.

Part of a complete field workflow

• Guided observations
  Step-by-step field instructions help participants follow the agreed method.
• Mobile and web access
  iOS, Android and a browser version support different field and institutional settings.
• Observation context
  Location and project metadata can travel with the measured colour and clarity values.
• Research access
  Data handling, extracts and integrations are defined for the deployment rather than assumed from a generic claim.

Research evidence across six programmes

The Mini and Midi Secchi literature is much larger than one paper. The 2025 international synthesis reports 927 disks produced and distributed across six principal programmes, with applications in lakes, coasts, estuaries and oceans. The published lineage begins with the 2019 printable device and includes real-time participatory monitoring, applied estuarine research, an instrumented “Lab on a Secchi disk” and satellite ocean-colour evaluation.

Use Mini Secchi

• Mini Secchi for iOS
• Mini Secchi for Android
• Mini Secchi web app
• Observation map
• Physical disk information from Brewtek

Rebuilt and improved in 2026

Pocket Science has signed a new contract with the University of Exeter and the US SOCON collaboration to rebuild and improve Mini Secchi. The new phase strengthens the participant software and research workflow around a method already established in the published record.

Earlier development was supported through the University of Exeter and the Gordon and Betty Moore Foundation. Mini Secchi’s continuing use includes the Participatory Ocean Color Network and SOCON connection between field observations and high-resolution satellite ocean-colour research.

Support and research deployments

For support, include the platform, app version, device, disk type and the step at which the issue occurs. Institutions planning a deployment can discuss participant guidance, data access, self-hosted services, integrations and multi-year support with Pocket Science.

Compare Mini Secchi with iSPEX2 and other citizen science water-quality sensor workflows.