Logging water tests in a planted aquarium with reminders and recurring tasks

In this part of the series on Krill and the Movement of water, we’ll cover:

• How to make a DIY color reader for recording water test results in a planted aquarium.
• How to manually log the results in Krill, and set up a recurring task to remind you to do it again in a week.
• How to read and visualize both the history of sample color change and ppm or pH levels over time.

Related

• Cron Timers — the same scheduling engine, exposed as a standalone Trigger node.
• SMTP Email Alerts — the executor of choice for “email me when I miss a test.”
• Lambda Python Executor — if you want to do something smarter than email on expiry.

Last verified: 2026-04-16