Monitoring priorities

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Was reading the thread on “Continuous monitoring vs intermittent testing” along with some other posts and it got me thinking about monitoring. I figured I would start a new post on it, so here goes.

I am interested in finding out a couple things.

  1. First off, what would be your list of parameters you feel should be measured in an aquaponics system - e.g. pH, temperature, EC, nitrite, etc… (but listed by priority - Highest to lowest). I am interested in seeing how much variation we might see in everyone’s answers.

  2. Secondly, has anyone done an analysis, cross referencing the price of probes and setup vs the benefit of the readings gained (continuous monitoring / not having to take snapshot readings daily/weekly) for the different parameters? (This would provide a good resource for those getting into automated monitoring - giving them a starting point to focus on.)

    Examples

  • Temperature: the cost is low for probes, they would be fairly accurate readings, but the benefit of continues monitoring would likely be somewhat low too (not a great variance over time with a good sized volume of water).
  • pH: higher cost probes then temp, ok accuracy readings (probe dependent) but with a higher value of the readout over time.
  • Nitrite and nitrate on the other hand - Cost of probes would be very expensive, but the importance of the readings are also high too.

I look forward to your answers.

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Good stuff, and a great conversation starter. Here are some thoughts to keep the discussion moving…

BTW, We have an open source awesome list that you can contribute to here. It has some of the most common sensors.

Evaluating sensors is, as you know, is unnecessarily difficult because it also depends on the environment they’ll be living in. The sensor may have stats for a lab-tested clean water environment but cannot operate at that level in a poorly filtered system, for example. We have goals of doing these types of evaluations in the future, but unfortunately nothing like that exists (that we know of).

Metric Selection

I have a background in technology-- so I have taken the same approach as a tech security analyst or a white-hat hacker may use to create a threat profile…

  1. Assessing what you’re trying to protect
  2. Assessing your greatest threat
  3. Assess the accessibility of prevention tools
  4. Implementing the tools to prevent these threats

This will obviously be different for every size and type of farm. That’s why I think the framework works well as it gets you thinking critically about it.

Example: If you’re trying to have high nutrients in your plants (protection) and prevent nutrient deficiencies (threat) then you implement tracking for pH because it’s within your means and know that it helps the availability of nutrients for plants. If lab/nutrient testing is within your means, implement this on a regular basis to know if nutrients are (in fact) in the water.

What we’ve seen in general for water quality:

  • Greatest threat prevention metrics: pH, Ammonia, Nitrites, Nitrates
  • Next implemented metric to prevent fish death: DO, Temp (if you are in cold climates esp)
  • Nice to haves: lab test results for full spectrum

What we’ve seen in general for greenhouse:

  • Greatest threat prevention (and cost effective): temperature / humidity for VPD and prevention of mildew for example
  • Next implemented metric: generic light sensors, power consumption
  • Nice to haves: light spectrum sensors and leaf temperature to prevent small harvest and optimize growth

I am curious what you’ve seen in your exposure to this stuff as well. Would love to hear your thoughts.

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Thanks. That is a great response. I like your analytical approach that you laid out. Just what I was looking for in my conversation starter.

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Here at Fontys University in Eindhoven, we are testing different electrodes.
pH, Nitrate and temperature.
We have a limited setup for the testing. The system is build to give the students opportunity to measure in a working system.

Testing ion-selective has several difficulties.
first most ion-selective electrodes aren’t meant to measure continues
second the electrodes suffer of the load biofilm forming at the membranes

We are also developing a method for measuring anions with ion-chromatography

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