How to Calibrate a pH controller with pH buffer Solutions

Here's a short video from Convergent Water Controls (CWC) illustrating how to calibrate our pH controllers using buffer solutions. Remember, it's important to have 2 pH solutions, usually one being pH 7 and another, usually pH 4 or pH 10. Watch the video for some handy tips & tricks.. Other topics that may interest you: - How to calibrate ORP on DIGICHEM Plus+: https://youtu.be/C1oMGsL1_uA - How to calibrate conductivity on DIGICHEM Plus+: https://youtu.be/Zb3v0neX6F0 Hi, I'm Larry from CWC. Today I'm going to explain to you how to calibrate a pH controller with pH buffer solutions. It's very important to have two solutions, a pH 7 and then either a pH 10, which I have here, or a pH 4. The mV output of a pH probe at pH 10 and pH 4 are identical, except that one is positive and the one is negative. So it doesn't matter which one you use. In the example here, I'm going to use a 7 and then a 10. A tip I can offer is that you can mark or write the number of the buffer. So I'm going to put 7 on this cap and I'm going to put 10 on that cap so that when you take the caps off, you don't get them confused and you don't contaminate the buffer solutions. Okay first step is to calibrate pH 7. I'm going to open the bottle and take the pH sensor out of the process. Best to give it a wipe with a tissue or paper cloth, rinse the end with a little bit of the buffer, give it a shake and then put it in the buffer solution. So with the probe in the pH 7 buffer, we moved the cursor to probe and press enter. Go to the calibrate menu. And what we do is we move the cursor to set P1. But before pressing enter, you can see that I have P1 set at 7, which is the zero point and P2 set at 10, which is the slope point. And the top left hand corner of the screen is the current reading, which is reading 6.5, but I want to calibrate it to 7. So I press the enter and you see it says OK next to the P1 point and then I move the cursor to save and I save the value. I will remove the probe from the buffer 7, ideally rinse it in a bit of water, give it a shake or a dry. Rinse the probe with buffer 10 and then insert in the 10 solution. Then go back into the calibration menu, but this time I moved the cursor to set P2, which is 10 and I press enter, it says OK. You move the cursor to save and I save the value and press enter. Now I escape because it's still in the 10 buffer, the reading should go to 10. There you go. As you can see, it's close enough, to 10. I'll take the probe out and give it a rinse but just for purposes of this demonstration, I'll pop it back into seven and you'll see the reading drop back down to 7. And if it does, which it should, you will then demonstrate that the controller is perfectly in calibration. It’ll take a bit of time to get down, but it will eventually reach 7.