Auto-dosing systems monitor EC, pH, temp, and other water variables, then they change those variables in real time. We use IntelliDose systems, which are easy to set up. A pH probe and an EC probe are set inside the mixing tank and send data back to the dosing system computer, which analyzes and makes decisions to turn a specific pump on or off.
The great thing about this is that for hydroponic growers, you don’t have to go out and hand dose all the time. (While aquaponic growers don't need to dose EC, you can still dose iron and pH.)
You can set up dosing systems to maintain certain variables, or to dose a specific solution on a schedule.
Say you’re using potassium hydroxide to dose pH, you would mix up the KOH in a bucket and the dosing system will automatically pull from that bucket when your system needs it.
Dosing systems will also do automatic top offs using a water sensor if you set them up to do so.
We run our system a bit slowly to give it time to mix in thoroughly before it doses again. This means that the pumps in the buckets moves smaller amounts at a time.
You can see in the video that we have two solutions set up. Part A and epsom salt are in one bucket, and calcium nitrate is in another. We also have an acid set up to drop pH on demand.
Quick tip: Make sure that your tank and your buckets are at the correct levels, or you might end up siphoning water or a solution into the wrong place.
There are several types of dosing systems out there, from basic pH systems (most useful for aquaponic growers) to middle-scale dosing systems like the one in the video, to huge dosing systems for large commercial scale operations.