Krill and The Movement of Water

Krill and The Movement of Water

It begins with a tortoise.

Meet "E," our baby Burmese Mountain Tortoise. Mountain tortoises are native to Myanmar and need cooler climates, consistent hydration, and proper humidity. Keeping E healthy means controlling water — where it comes from, where it goes, what's in it, and how fast it moves.

That’s where Krill comes in.

This is a series about my planted aquarium lab — how city tap water moves through filters, into the aquarium, gets cycled through sensors and processors, and then gets tapped off to feed a hydroponic system, a vivarium, and E’s jacuzzi. Multiple Raspberry Pis running Krill Server coordinate everything in real time, with no cloud, no subscriptions, and no single point of failure.

What’s in the series

• Relays and Solenoids — Controlling water flow with GPIO pins, logic gates, and Zigbee smart plugs
• Leak Detection — Using logic gates as safety interlocks to shut everything down if water goes where it shouldn’t
• CO2 Reactor with Color Sensor Feedback — The showpiece: a DIY CO2 injection system with a color sensor that reads pH indicator solution, detects dangerous CO2 levels by color shift, and triggers automated shutoff

How Krill works (the short version)

Everything in Krill is a Node. A data point stores a sensor reading. A cron timer fires on a schedule. A calculation transforms data. A logic gate makes decisions. You wire them together and the system reacts in real time.

Nodes live on servers. Servers auto-discover each other on your network and form a mesh. You see it all in the app — a live swarm of nodes executing, data flowing, alerts firing.

A simple swarm: a timer reads a counter data point, adds 1, and writes it back every 5 seconds.

If you’re the kind of person who has a Raspberry Pi in a closet, a reef tank in the living room, and a Python script duct-taped to a cron job — Krill was built for you.

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Last verified: 2026-04-06