Step guide on calibrating a pH pen. – Gro Indoor
Skip to content


How to Calibrate a pH Pen

by 09 Apr 2023

How to Calibrate a pH Pen

Every good grower knows that maintaining the pH balance is essential to ensure healthier growth for their plants. You should also know that cannabis plants absorb nutrients better when the plant’s pH value is balanced. However, if the plant’s pH level is too high (or too low), your plants may show nutrient deficiency symptoms.

The best way we suggest you maintain the pH value is by measuring it with a pH pen. However, pH pens tend to lose their accuracy with time. By timely calibrating it, you can make sure that they are working correctly. Here’s a step-by-step guide to help you calibrate your pH pen after every few months.

What to look for while calibrating a pH pen

You need to see if your pH calibration is accurate as soon as you take it out from the pack. Since you need to make sure that your reading is as precise as possible, there are other indications that you should be on the lookout for. Let’s learn about them!
1 If you notice that the reading is inaccurate to what you were expecting, your pH pen needs calibration.
2 It needs calibration after you cleaned or performed hydration on it.
3 If you see that the checkmark has disappeared a month past the first calibration, then it’s time to calibrate the pH pen.
4 A change in batteries also impacts the calibration of your pH pen. You need to calibrate the pen with either a “7.0 and 4.0 pH solution” or a “7.0 and 10.0 pH solution”. However, it depends on the current reading value.

First Step: Cleaning the Probe

Aside from using a brand-new pH pen, it would help if you cleaned the pen before calibration. Apart from that, you also need to hydrate the probe before usage or after cleaning.

Second Step: Rinsing the Pen with pH 7.0 solution

' After you’ve hydrated your pH pen with freshwater, you have to place it in the pH 7.0 solution. Now, it’s time to wait for the reading to normalize.

Third Step: Pressing the cal button

This step may seem like a simple one, but it’s an essential one. In other words, you must push the cal button until CAL 7 appears on the display screen. The display interprets that the pen now has a point 1 calibration.

Fourth Step: Rinsing the Probe again in a pH 4.0 solution

The next step is to clear the probe in freshwater, and you have to place it in a pH 4.0 solution. However, if you are expecting a value of above 7.0 pH, you have to use a pH 10.0 solution. Now, it’s time to wait for the reading to normalize.

Final Step: Pressing the cal button until You Receive a Point-2 or Point-3 calibration

The final step is to press the cal button until you see a CAL 4 or CAL 10 on the screen. Keep in mind that the value depends on what type of solution you’re calibrating. However, when you’re following the steps for a 3-point calibration, repeat them using pH solutions (4.0, 7.0, and 10.0).

Final Words

Keep in mind that the calibration is a relatively simple method. The abovementioned steps are common to calibrate various pens; but, don’t forget to consult your instruction manual for further guidance. Or you could connect with to resolve all your concerns. We have all the expertise and the products to help you flourish as a grower.

May 10th 2021
Prev Post
Next Post

Thanks for subscribing!

This email has been registered!

Shop the look

Choose Options

Edit Option
Back In Stock Notification
this is just a warning
Shopping Cart
0 items