Injector & Dosing Calibration — Making the Ratio Match the Reading
Ratio-based injectors vs EC-controlled dosers, the stock-tank dilution-factor math, why A and B need separate channels, and the verify-at-the-emitter calibration routine that catches drift before the crop does.
The water-room lesson introduced batch vs injector delivery. This lesson is the injector deep dive: at commercial scale you rarely hand-mix a reservoir — a proportional injector or an EC-controlled doser meters concentrate from stock tanks into the water line continuously. That's a huge efficiency win and a new failure mode: an injector drawing 10% off ratio will feed every plant in the room the wrong EC, silently, batch after batch, until a tissue test or a lockout tells you. The discipline is understanding the two control philosophies and verifying the machine against a meter — never trusting the dial.
| System type | How it controls dose | Strength | Watch-out |
|---|---|---|---|
| Ratio / proportional injector | Fixed dilution ratio (e.g., 1:100) of concentrate into water flow | Simple, no power/electronics needed | Output EC drifts if source-water EC changes; verify at emitter |
| EC-controlled doser | Meters concentrate to hit a TARGET EC in real time via inline sensor | Self-corrects for source-water swings | Only as good as its EC probe — needs regular calibration |
| Multi-channel doser | Separate pumps for A, B, acid, supplements to targets | Precise, keeps A/B apart until diluted | More probes/pumps to calibrate; more to drift |
The rest of this lesson is for members
Unlock every department, SOP, calculator, and setpoint table — plus Leaf, your AI consultant, and interactive diagnostics.
- All 11 departments
- Coco & rockwool tracks
- The full SOP library
- Leaf AI consultant