Runoff, what is it, and what does it tell you? Well, traditionally speaking, runoff used to tell you if you're getting build up of nutrients inside of your medium. That was an important part because there always used to be a question of what's going on in the black box. With the TEROS 12, you no longer have to worry about this. We have an accurate reading of where your water content and EC is at all times.
Now, what does runoff volume tell you? Well, it gives you a good indicator if you are over-watering your plants. Even with the substrate sensors, we only want to see typically a 30% runoff. So with the substrate sensors, we'll see where your water content rises to, maintains, and dry back, where your EC is at all times, where your incoming volume will tell you to your outcoming volume is with the ratio of in to out and how much that percentage is. We don't want to really exceed 30% runoff, so some of this could give you a better accurate reading of how to make adjustments in your irrigation.
What does runoff pH tell you? This usually gives you an indicator of what nutrients your plants are uptaking. Now if you remember from previous episodes, we talk about what happens in the substrate. The roots always want to remain neutral. So as it uptakes positive ions, it's going to release more positive ions. Typically, that's going to lower the pH of your solution. Now, this is not always a fact because with each medium, there's actually a relationship of how the plants uptake nutrients and what actually happens within the medium. Some of them have a cashew exchange, so that could change your outcoming pH. The main thing to focus on is always your incoming pH. And if you focus on your incoming pH and use your outcoming pH as only impossibly an indicator of what nutrients your plants are uptaking, this might give you an idea of where you should change and what you should do as you're going through different phases of growth.