4 Best pH Meters for Hydroponics

Maintaining proper water chemistry is essential for running a successful hydroponic garden, and for that you’ll need the best test equipment you can find. Among the most important pieces of equipment is a pH meter.

Why is pH important in hydroponics?

pH is a measure of acidity. The pH of your garden matters to your plants because it determines how well your plants will be able to absorb nutrients from your hydroponic nutrient solution. Nutrients react with the molecules in your water differently at various pH levels, becoming more or less available to your plants for absorption. Most of the nutrients your plants will need are most available at roughly the same pH level, which gives you your ideal pH range for the water you input into your farm. This is usually between 5.5 and 6.5.

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Best pH Meters for hydroponics

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Our first pick of pH meters is the Apera Instruments AI311. The Apera pH meter’s user-friendly features make it a wonderful choice for someone who wants accurate and easy pH readings. This probe will simultaneously measure temperature and pH at the same time and display both values on an easy-to-read LCD screen.

Since the pH reading of digital meters varies depending on temperature, this feature helps you be sure that your probe is measuring the pH accurately each time. Plus, you don’t have to spend time inputting the temperature with each use.

Users love the ease of use of this meter. According to buyers, Apera’s meter is easy to calibrate and consistently gives out accurate pH readings over multiple uses. This meter gives out stable readings when exposed to a solution, which is a good indicator of its ability to measure pH accurately.

Some meters drift in their readings and make it hard for a user to know exactly which of the multiple readings they are getting are accurate, but the Apera meter keeps its output tight. One drawback to this meter is that the temperature probe takes a few minutes to warm up and begin accurately reading water temperature, so it’s recommended by reviewers that you give the meter a little bit of time to get going before you attempt to measure your water.


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Second up is Bluelab Hands Free pH meter.

This meter is one of the most high tech options and also one of the priciest. It’s a big investment to make, but it comes with some serious advantages, especially for people running larger operations. This meter is installed into your garden permanently and monitors the pH level of your water constantly.

If the water falls out of the specified range, the meter will automatically adjust the pH for you. If something is wrong with the system, the meter will flash an alarm at you to make sure you see it. When Bluelab says hands free pH monitoring, they absolutely mean it.

Buyers totally love their Bluelab probe, especially its easy setup and calibration. Among the most loved features is the auto dosing feature that saves users the time of having to test and correct the pH on their own and its dependability. Despite its price tag, buyers agree that this meter is worth the investment.


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If you’re looking for the cheaper products from a high end brand, you can also check out the Apera AI209 pH pen.

It’s about as cheap as they come from this respected brand. With temperature recognition and auto calibration, you still get some of the best features of the more expensive Apera products in this bite-size mini version at a much cheaper price point.

You can even wear it around your neck or wrist for easy access and fall protection with the included lanyard! As true to the Apera name, this pen will let you know when your reading is stable and give you a warning if it detects that the calibration was off. When you’re not using it, you can store it and its included calibration solution in the included carrying case.

Users agree that this meter is a solid purchase. They love its durability, reliability in getting accurate pH measurements, and its ease of use. Buyers note that to get the most out of the pH pen, it’s important for you to follow the storage and use instructions, but overall it is a consistent tool and is worlds better than some of the cheaper meters being sold. Reviewers also noted that Apera will throw in some free calibration solution with your purchase if you agree to leave a review.


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Best budget pH meter for hydroponics

If you can’t afford some of the big names in pH meters, or if you just aren’t ready to invest a lot of money into hydroponics until you’re sure it’s for you, there’s no need to go off and buy flimsy litmus strips. There are still plenty of options that fall within a lower end budget.

Our budget pick is this pen pH meter from Qustsell.

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This pH meter comes in at an incredibly affordable rate. It’s small, easy to calibrate, and accounts for temperature on its own. It comes with a carrying case and powder you can dissolve to create the solution you’ll calibrate the meter with along with the pen itself. This meter is battery operated and touts an accuracy within .01 pH with correct calibration, so it’s certainly up for use in prepping water for your hydroponics garden.

Buyers note that you will have to be careful with the calibration and do it often, but it does the job, and you’ll get your money’s worth.

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How do you test pH levels in hydroponics?

Depending on the type of testing kit you choose, the specifics of testing the pH will vary slightly, but the general process remains the same for almost all meters. First, you will calibrate your meter. Usually, this involves using at least one test substance whose pH you already know.

You’ll expose the meter to these known substances and then tell it what the pH is supposed to be. You will have to repeat this process until the meter can accurately measure the pH of these known substances on its own, although it usually only takes one or two tries.

After the meter has been calibrated, you rinse off any calibration solution with deionized water, dry it gently, and expose your meter to the water you want to test. Many meters on the market will also require you to input the water’s temperature before you test it, since the reading on the meter can be affected by how hot or cold the water is. Be sure to read the specific directions of your meter thoroughly before use, and clean and properly store the meter after use.

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How accurate is a pH meter?

The accuracy of your pH meter is very much dependent on how well you calibrate it, as well as its precision. The most expensive equipment out there won’t be good enough to help you if you don’t calibrate the meter correctly. Likewise, if you are careful with the calibration process, some of the lower tech options can be more than accurate enough to get your water within the ideal pH range.

In general, the higher quality pH meters will be more precise than lower quality meters. This can be a problem if you are edging toward the extremes of the ideal pH range, since a low precision meter could measure the pH to be within the ideal range when it is actually outside of it. It is important to invest in the highest quality pH meter that you can in order to avoid these issues, and be sure to take extra care during the calibration process.

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What is slope of pH meter?

The slope of the pH meter deals with the relationship between pH and voltage of your water. This information is useful to you, because you can use it to identify if there might be problems with your meter. If the slope is very low or unstable, it could mean that your probe isn’t measuring the pH accurately, either because of user error or the probe getting old and needing service or replacement.

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How do you fix the pH of your water?

If you’ve tested your pH and it’s way out of whack, there are easy ways to adjust your water back to ideal ranges. Since pH is a measure of acidity, you either have to add an acid to make the water more acidic, or add something alkaline to make the water less acidic. It is important to remember that you can’t just add any acid or alkaline solution to the water.

You must use specialized products that have been developed specifically for adjusting the pH of water. Otherwise, you risk introducing chemicals that are dangerous to your plants. Once you identify an issue with your water, simply add the necessary amount of acidic or alkaline solution to your water until it tests to be within the desired range.

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