The 9 Best pH Meter Choices For Hydroponics

Finding the best pH meter is quite a chore. In fact, hydroponic gardening, in general, can feel a lot like an undergraduate-level science class at times!

Unlike soil-based gardening, growers need to keep track of every little detail. Your water quality, and especially the pH level of your nutrient solution, is vital to track. Failing to properly monitor your nutrient solution can result in sickly plants and a healthy dose of frustration.

When I first got into hydroponics, I didn’t take my water quality seriously. After all, in traditional soil gardening, a stockpile of lime and compost kept my soil pH right where I wanted it. But in hydroponics, you’ll need a little more attention to detail. So investing in the best pH meters for hydroponics to check your values makes lots of sense!

9 Best pH Meter Reviews

Bluelab pH Pen Pocket Tester

The Bluelab pH pen is the best pH meter for hydroponics out there. It measures pH and water temperature, and the back-lit LCD display makes it easy to read. I’ve written a more in-depth review of the Bluelab pH pen here, but the basic idea is that it’s my favorite digital pH meter and the one I use in my gardens on a daily basis.

Pros

• Easily measure pH and temperature with one reading
• Fully waterproof
• Sponge in cap to keep the probe moist
• Comes with 1-year limited warranty

Cons

• Calibration kit not included
• Fragile sensor bulbs

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Hanna Instruments HI 9813-6N pH/EC/TDS Meter

If for some reason you don’t like the Bluelab line, the Hanna combo meter is a great alternative. Hanna is another extremely reputable manufacturer of pH and combo meters, and although I personally use Bluelab, many of my friends are devoted Hanna fans.

One of the best features in this combo meter is the built-in calibration reminder. No more forgetting to calibrate and wondering why your readings are so off!

Pros

• Measures pH, temperature, electroconductivity (EC), and total dissolved solids (TDS)
• Easy to read display
• Simple operation and calibration
• Built in calibration reminder
• 7.0 and 4.0 calibration
• Waterproof

Cons

• Cap has no seal lock
• No anti-slip feet

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Bluelab Combo pH Meter

The Bluelab Combo Meter is the de-facto standard in combination pH, temperature, and PPM/EC/TDS meters. It’s the one that I recommend most often as well as the one that I find most growers to be satisfied with.

Pros

• Measures pH, temperature, and electroconductivity (EC)
• Comes with replaceable double junction pH probe
• Auto off function
• Automatic calibration

Cons

• Fragile probe
• Not completely waterproof – only the probes are

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Apera Instruments AI311 Premium pH Test Kit

While it requires some specific care and maintenance, this pH water tester is a great option. Apera Instruments has a number of different models (as you’ll see further on), but this one is their top of the line. It comes as a complete kit including calibration solutions, a quality glass probe, and even storage and battery options.

Pros

• Easy calibration
• Replaceable probe
• 3-color LED window identifies each mode of operation
• Fully waterproof

Cons

• Must be protected from freezing conditions
• Replacement probes can be pricey

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Oakton EcoTestr Pocket pH Meter

The Oakton EcoTestr is an old standard for a pocket-sized ph tester. While it’s often forgotten when newer devices are unveiled, I find it to be a reliable option that’s usually a few dollars cheaper than newer models.

Pros

• Good budget option
• Measures pH and temperature
• Waterproof and dust proof
• Convenient pocket size
• 1-year limited warranty

Cons

• Doesn’t last as long as the Bluelab pH pen
• Must keep calibrated more often

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Bluelab Guardian pH Monitor

The best combo meter is the Bluelab Guardian Monitor. This meter is pricier than the other options but is ideal for serious growers with a large budget. Because it’s always on and monitoring your garden, you’ll know the instant that your metrics get out of whack.

If you are a larger-scale grower with some money to invest in your monitoring system, then you absolutely must go with the Bluelab Guardian. I know of no other good solution for this level of live-monitoring.​

Pros

• Large displays
• Flashing alarms if numbers are out of range
• Comes with a range of accessories

Cons

• Sometimes the digital displays bug out (only a few reports of this)
• You can burn through probes quickly without proper care and calibration

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Apera AI209-T Value pH Test Kit

The Apera Instruments AI209 is their value-level test kit, and it’s a surprisingly popular one. This pH tester for water is portable and easy to use. The kit includes all of the necessary calibration solutions to ensure you’ve got accurate readings. If you’re looking for something inexpensive but all-inclusive, you can’t go wrong with the Apera Instruments AI209.

Pros

• Easy to calibrate
• Offers dual display of water temperature and pH level
• Comes with probe cleaning brush & calibration solutions
• Fully water and dust proof

Cons

• Can get bubbles in the probe sensor that need to be dislodged
• Takes about 30 seconds longer than manufacturer says for readings

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Apera SX620 pH Pen Tester Kit

This narrow Apera Instruments pen tester has a narrow probe that easily tests the pH level in everything from test tubes to large reservoirs. As with the other Apera Instruments devices we’ve covered, this device comes with a full kit and will require regular calibration. Pocket-sized, it’s a great small device for keeping tabs on your solution.

Pros

• Slim, replaceable probe
• Includes calibration solutions, pocket-sized storage case, storage solution
• Fully dust and waterproof, floats in water

Cons

• Small screen can be difficult to read
• Takes a little longer than expected to test pH levels

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Dr. Meter Digital pH Meter

If your budget is a bit too low for the other pH testers on our list, consider this Dr. Meter hydroponic pH tester. It tests both temperature and pH levels at a budget price. While not as fancy or specialized as some of the pricier options, the Dr. Meter device is a reasonable choice.

Pros

• Extremely well-priced for a decent meter
• Easy to calibrate
• Has a nice large screen that’s easy to see

Cons

• Batteries are a bit difficult to install
• Replacement probes do not appear to be available

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Helpful pH Testing Accessories

After dropping a large sum of money on a digital meter, I’m sure that the last thing you want to think about is buying more accessories.

Unfortunately, your meter won’t be much use to you without a calibration solution and care kit. These kits help keep your pH meter accurate and operational, giving you better results and preserving your investments.

Bluelab Probe Care Kit

If you decided on a digital pH meter from Bluelab, their probe care kit is both affordable and the best option. It’s designed to work with the full range of Bluelab products and comes with a bottle of 4.01 reference solution and 7.0 reference solution, available in 8 oz and 1-quart quantities.

Pros

• Designed for use with Bluelab products
• Comes with probe cleaner, tool, and plastic cups

Cons

• Only comes with 2 x 20ml sachets

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General Hydroponics pH 4.01 & pH 7.0 Calibration Solution

General Hydroponics also has a kit that comes with one bottle of pH 4.01 solution and one bottle of pH 7.0 solution. This is a good option if you either don’t have a Bluelab meter, or you just want a large quantity of solution without any of the extra bells and whistles.

Pros

• General Hydroponics is a highly reputable brand in hydroponics
• You get much more for the money

Cons

• Does not come with cleaning supplies

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All of this might seem like a lot of information to take in, but I promise it is worth it.

Monitoring the pH of your hydroponic solution is the single most important thing you can do to ensure a thriving crop and happy plants.

To do that, you need the right tools, and you need to know how to care for them.

One of the things I have learned as a gardener is that there are two things that can ruin a tool: buying a cheap, poorly made product and failing to care for it properly. If you have invested time and money into your hydroponic system, don’t waste it by buying a cheap pH meter.

A good meter will pay back your investment, and a bad one will cost you more in the long run.

Why Monitoring Your pH is so Important

So why does pH matter? The pH of any growing system, be it hydroponic or soil, plays a large role in the growth of your plants. It’s not just a matter of some plants preferring more acidic soils or other plants preferring more alkaline – it determines the nutrients that are available to your plants.

Look at it this way: you take the time to ensure your plants get all of the nutrients that they need. But none of this matters if your pH is off. Unless your test shows you’re in the right range, your plants won’t be able to absorb the nutrients, which means you have wasted time and money adding them to your system.

Still confused? Check out my article on pH and nutrient availability for a complete breakdown of the relationship between pH and nutrient availability.

But for now, what you need to know is that it matters, and you need to monitor it.

Most plants do well with a pH of 5.5 to 6.5. While some plants have specific requirements, a good rule of thumb is to stick to the “sweet spot,” which is around 6.2.

Keeping your system slightly acidic has another advantage as well: many waterborne algae varieties don’t like acidic environments. Since we don’t like waterborne algae, this is a win-win situation.

How Does a pH Meter Measure pH?

Now that we agree that monitoring pH is crucial to the growth of your hydroponic garden, let’s talk about how these meters work.

Your pH meter measures the hydrogen-ion concentration of your water. This concentration indicates whether the solution is acidic or alkaline by determining the difference of the electrical potential between a reference electrode and a test electrode.

Personally, my brain has a hard time wrapping around this sort of thing, so I’ll keep it simple. Your meter has a glass electrode, which is sensitive to hydrogen ions, and a reference electrode, which is stable. The difference between the two tells the pH meter what the pH of the liquid is and allows you to adjust your solution accordingly.

Manual pH Testing vs. Digital pH Meters

There are two basic types of pH meters: manual and digital. If you are a serious hydroponic grower, then you probably already use a digital pH meter. If you are just getting started, though, I will give you the breakdown of the pros and cons of manual pH testing vs. digital.

Manual pH testing

Manual pH testing is done with a simple kit, kind of like the water pH test kit you use to test the pH of a pool. Manual water pH test kits are much cheaper than digital pH meters and they are easy to use.

Upsides to Testing Your pH Manually

Since there are no parts to a manual pH kit that require care, you don’t need to worry about things breaking or corroding over time. These traits make manual testing kits ideal for growers just getting started in hydroponics.

Downsides to Manual pH Testing​

The downsides of manual pH testing make them less than ideal for serious growers. It takes a lot more time and effort to work with manual pH test strips or pH fluid.

Time management becomes a barrier to serious growers, especially when compared to the simplicity of a digital pH meter.

Accuracy is also an issue. pH strips can be hard to read, especially if you are color blind. This can lead to readings that are way off, which will negatively impact your system.

Digital pH meters

Digital pH meters are the way to go it you plan on doing a lot of hydroponic growing. These meters should last a lifetime if you take care of them, and they are much more accurate than manual pH meters and pH test strips if they are calibrated properly.

Digital meters are fast, too, letting you test quickly and frequently, making them far more efficient than manual pH meters.

Downsides to Digital pH Meters​

Of course, all of this convenience and efficiency comes at a price. The best digital pH meters are more expensive than manual pH meters, and they also require more maintenance than manual meters.

Digital pH meters must be calibrated frequently in order for them to remain accurate, and without proper care, your expensive digital pH meter breaks down.

Calibrating a pH Meter

If you choose to go the digital route, as most of us eventually do, you need to know how to calibrate your pH meter. Think of calibration like tuning a musical instrument. You need things to be tuned to the right key, or the entire musical piece will be off.

Before you begin, you need a buffer solution. A buffer solution is basically a laboratory certified standard reference point for your pH meter. Most buffer solutions are liquid, although you can buy them in powder form and mix them with water if you prefer.

Once you have your buffer solution, follow these steps to calibrate your pH meter:

1. Place your meter into the buffer solution to get accurate readings
2. Adjust the reading on your meter to match the buffer solution according to the manufacturer’s instructions (these can differ for digital and analog meters)
3. Repeat if necessary in an additional buffer solution of a different pH for higher accuracy
4. Calibrate your pH meter once a week if you use it regularly, or at least once a month
5. Always calibrate your pH meter when you replace a sensor for accurate readings
6. Your pH meter will come with instructions. Make sure you read them before calibrating your meter just in case the steps are different.​

Caring for your pH Meter

All of that calibration won’t matter if you don’t take the time to care for your pH meter.

As boring as most directions usually are, the first thing you should do when you get a new pH meter is read the instruction manual that comes with it. The instructions should tell you how to care for your pH meter. If they don’t, call the manufacturer and ask them.

In general, there are several things you need to do for every pH meter:

• Read the instructions
• Keep it calibrated
• Store meters with storage solutions in the cap upright for optimum saturation
• Lightly swirl your meter in the storage solution to get rid of air bubbles
• Don’t touch the sensor electrode or reference cell, as the oil on your skin can damage the sensor and affect readings
• Store away from high heat and humidity
• Don’t store your sensor in distilled water
• Handle with care