Continuous hydroponic nutrient monitoring is challenging because a nutrient solution is constantly changing. Plants take up water and nutrients at different rates, pH can rise or fall, EC can become more or less concentrated, and source water and environmental conditions can influence your readings.
Continuous monitoring gives growers visibility into these changes around the clock, helping identify trends and unexpected changes that can be missed between manual measurements.
Key takeaways
- pH and EC can change as plants take up water and nutrients.
- EC measures overall nutrient solution strength, not individual nutrients.
- Source water can influence your starting pH and EC.
- Reliable monitoring depends on clean, well-maintained probes and correct pH probe calibration.
- Monitoring pH, EC and temperature together provides a clearer picture of nutrient solution conditions.
Why do pH and EC keep changing in hydroponics?
A hydroponic nutrient solution does not remain static after it has been mixed. Plants continually interact with the solution as they take up water and nutrients.
pH can change through plant uptake, source water and nutrient additions. EC can also rise or fall as plants take up water and nutrients at different rates.
This means a reading within your target range at one point may change as growing conditions and plant demand change. Continuous monitoring helps growers see these changes as they happen rather than relying solely on individual spot checks.
Why can't EC tell you exactly which nutrients are in your solution?
EC measures the overall concentration of dissolved ions in your nutrient solution. It cannot tell you whether those ions are nitrate, potassium, calcium or another nutrient.
Two solutions could therefore have the same EC while containing different proportions of individual nutrients. EC is best used as an indicator of overall nutrient solution strength, alongside pH, temperature, crop requirements and a correctly formulated nutrient program.
Learn more about EC, PPM, TDS and nutrient strength.
How do water quality and temperature affect monitoring?
Every nutrient solution starts with water. Source water may already contain dissolved ions that contribute to EC, while its alkalinity and carbonate content can influence how easily pH can be adjusted and maintained.
Temperature is also important. Conductivity readings are temperature dependent, which is why Bluelab conductivity products automatically compensate for temperature.
Monitoring pH, EC and temperature together gives growers a more complete picture of changing nutrient solution conditions.
Why does probe maintenance matter?
Continuous monitoring depends on reliable measurements. pH probes need to be kept clean, hydrated and regularly calibrated, while conductivity probes should be kept free from nutrient salt buildup and other contamination.
Learn how to clean your pH probe and clean your conductivity probe.
What is the difference between spot testing and continuous monitoring?
Handheld meters provide a snapshot of conditions at the time you take a measurement. Continuous monitors remain connected to the growing system, measuring pH, EC and temperature throughout the day and night.
This makes it easier to identify trends and changes between manual measurements. Continuous monitoring can also alert growers when conditions move outside their chosen ranges, allowing them to investigate sooner.
Spot checks still have value, particularly when verifying an unexpected reading or troubleshooting a growing system.
Which Bluelab solution is right for your grow?
The right approach depends on how frequently you need to measure and how much visibility you need into your nutrient solution.
For manual pH, EC and temperature measurements: The Bluelab OnePen combines all three measurements in one portable device.
For continuous monitoring: The Bluelab Guardian Monitor Wi-Fi continuously tracks pH, EC and temperature, helping growers see changes between manual measurements.
For monitoring and automated control: The Bluelab Pro Controller Wi-Fi continuously monitors pH, EC and temperature and can automatically control pH and nutrient dosing.
