Sourcing nutrients: Process automation


So one of the things I’m interested in outside of the actual PFC, is the nutrients used in the machine. It would probably be easiest (and cheaper) just to buy them from a gardening supply but, I’m curious if anybody in the community has looked into making their own.

Things like using a solar panel with the Birkeland-Eyde process for producing Nitric Acid for bio-available nitrogen. Waste processing to extract Struvite as a phosphate source. Hard Wood ash for extracting potassium (and possibly using the burning wood to produce heat or biocrude to run a generator) etc. I’ve even looked into things like extracting Magnesium from sea water. The end goal being, to get as close to self sufficiency and automation as possible.

Any help with this subject matter would be appreciated.


I stumbled upon this video. I was thinking of something similar but I guess proper dosing (for smaller nutrient tanks) would be a bit difficult.

Syringe Pumps - Peristaltic Dosing Substitute & DIY Aeroponics

You think try with this solution?

They are not the possibility to add the process directly in the Arduino<>Raspberry for don’t have two different controller? (and add monitoring to the main screen without other lcd)


I personally would opt for a simpler, cheaper and more precise solution. My idea is as follows:

I would attach a IV admin kit (~0.50$ per set) to the nutrient containers. Using the roller clamp, you can set the flow to a very precise rate.

Using a small servo I would start/stop the flow by squishing the tube.

This would allow you dose the nutrients with much more precision. No need for additional controller-electronics, meaning you could use the already existing hardware to control the servos. This concept would be very affordable and easy to order, replace and extend. :slight_smile:


Ok i see! It’s one solution!


Where to begin! This is something I have looked into a lot on my own, that video of the Mixologist is a great start for this topic.

I have/do use systems that automatically dose nutrients like the Grobot Evo:

There tend to be a few things that always end up going wrong.

  1. Tubing either breaks/gets clogged. Remember, lots of these nutrients build up deposits over time.
  2. Nutrients also have shelf-lifes that change based upon when they are combined.
  3. Different plants need different solutions, this means you are left with two options. Having a “mixing tank” where the nutrients are combined, and then sent to the end destination reservoir. Or, you have to have multiple dosing/monitoring systems. This requires multiple sensors, and actuators thus raising price.
  4. All liquid nutrients recommend “shaking” prior to use, this is a necessary part of the process, that if you just pump nutrients from the bottom of a solution that has settled will give you incorrect doses.

I have tested solutions using an IV drip, this is a good start, when sourcing the pricing though, if peristaltic pumps can be obtained for $5-10 each, they really are the best solution using moving parts. I am currently working on a nutrient dosing module that will run using only one pump. MIT appears to have a similar solution using the Dosatron. Let me know if you’d like more information regarding what I’m working on.

To answer the original question though regarding sourcing raw nutrients, I wish I knew more about chemistry to answer you, I would be very curious though to know what you find out. The best answer I have though if you want to make a self-sustaining system is to look into aquaponics.

Thank You,
Peter Webb.


Hi @Webb.Peter and @Richard,
I am trying to find all the components for the FC2 in Spain. Unfortunately the peristaltic pump in the BOM is not sent to Spain. I found an alternative in Aliexpress. It is very similar but there are two points that need to be checked:

  • Flow rate:

    • Original:0-100 ml/min
    • Alternative: 0-200ml / min (without speed control circuit)
  • Rotate speed:

    • Original: 0.1-100 rp
    • Alternative: No info

Is the difference in the flow rate important or does not matter? Would it be necessary to be sure about the rotate speed in the new one or not?
Thank you for your help!


Original one:



So the bad news is that those will be quite different, I’m not familiar enough with the software to say how exactly the dosing pumps will works perhaps @webbhm, @ferguman, @adrianlu may have a better idea.

The real question is: How does the software regulate PH/Determine Nutrient Doses? Either it is constantly monitoring sensors, and will make slight adjustments over time by turning the pump on for 1 second until the “goal” is reached, or it calculates internally how much to add and then executes. The first option make it much less important which pump you used, but if the second option is used then it could really make an impact. For example: if it calculates you need an EC of 1.2 and that requires 100 ML of nutrient then it will turn on for 1 minute, in your situation that would result in 200 ML being added.

Hope that helps,
Peter Webb.


Thanks @Webb.Peter, for your answer, I see your point.
In that case the main question would be if it is possible to adapt the software easily for pumps with different flow rates or not, am I right?


You are correct, that is where I asked a few other people who know the software better than I that question.

If you find out please let me know.


Thanks a lot!
I will try to contact them. Of course I will let you know.