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Ingredient

pH sensor

Also known as: pH probe, glass electrode pH probe

Glass-bulb electrode that generates a small voltage (~59 mV per pH unit) proportional to hydrogen-ion concentration. The defining sensor for any closed-loop hydroponic, aquaponic, or fermentation system; pH is the master variable that controls nutrient availability. Probes pair with a signal-conditioning module that buffers and amplifies the high-impedance electrode signal to a usable analog voltage. ~$15–60 for hobbyist (Atlas Scientific, DFRobot); ~$100–300 for laboratory-grade. Two-point calibration (typically pH 4.0 and pH 7.0 buffer solutions) is mandatory and drifts with use.

Inputs / outputs

  • Probe output: ~59 mV per pH unit (Nernstian); 0 V at pH 7
  • Conditioning module: typically outputs 0–3V or 0–5V analog after buffering and gain
  • Power: 5V to the conditioning module, ~5 mA
  • Range: pH 0–14 (most probes accurate ±0.1 in the 2–12 range)
  • Response time: ~10–30 seconds for stable reading after immersion

Solves / unlocks

  • Hydroponic pH-up / pH-down auto-dosing (5.5–6.5 typical setpoint range)
  • Aquaponic pH stability monitoring (rapid drift indicates fish or biofilter trouble)
  • Beer / mead / [[kombucha|kombucha]] pH tracking through fermentation
  • Soil slurry pH (with proper sample prep) for amendment planning
  • Compost-tea brewing optimization

Constraints

  • Never let the probe dry out — glass-bulb membranes destroyed by dehydration. Store in storage solution (KCl) or pH 4 buffer.
  • Calibrate weekly in continuous deployment; daily in critical-control loops.
  • Probe lifetime is 12–24 months in continuous use; treat as consumable.
  • Temperature compensation — pH varies ~0.003 per °C; pair with temp sensor for accuracy.
  • Reference junction clogs in dirty water (algae, biofilm) — flush with KCl or replace probe.

Source

See also

Auto-generated from this entry’s typed relations: frontmatter, grouped by relation type so the editorial signal isn’t flattened.

  • Member of: [[ingredient]]
  • Combines with: [[ec-tds-sensor]] · [[peristaltic-pump]] · [[arduino-uno]] · [[esp32]]

What links here, and how

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Practical

combines with

  • Aeroponics pH probes pair with EC probes for aeroponic nutrient management as in any hydroponic technique
  • Aquaponics aquaponics demands continuous pH monitoring — fish prefer 6.5–7.5, plants prefer 5.5–6.5, nitrifying bacteria prefer 7.0–8.0; the operator manages a compromise
  • Controlled-environment agriculture CEA nutrient management requires continuous pH monitoring alongside EC
  • EC / TDS sensor EC + pH together = the minimum sensor pair for hydroponic nutrient management
  • Fruiting chamber humidity / CO2 monitoring drives chamber design at all scales beyond hobby; mushrooms are particularly sensitive to fresh-air exchange
  • Hydroponics pH probes pair with EC probes — both required for any serious hydroponic operation
  • Peristaltic pump pH-up and pH-down dosing pumps in hydroponic reservoirs

contains

combines

shares substrate with

  • Vertical farming pH probes pair with EC probes in every commercial vertical farm

10 inbound links · 5 outbound