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Apera Instruments

APERA INSTRUMENTS AI209 Value Series PH20 Waterproof pH Tester Kit, ±0.1 pH Accuracy

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Availability: In Stock.
Fulfilled by Amazon
Arrives Tuesday, Sep 22
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Style: Regular Kit


Features

  • Easy auto. calibration with buffer recognition; auto. temp. compensation (ATC) ensures accuracy in various temperatures (32 to 122F)
  • Backed by Apera quality pH sensor with low impedance, ensuring high response rate
  • Comes in a rugged carrying case with pH 4&7 buffers and a lanyard
  • Auto recognition of stable values improves consistency, so you don't have to guess when to manually hold measurement
  • Up to 2000 hours' continuous operation, powered by AAA batteries

Description

Simply the most reliable pocket pH tester with the best value for general- purpose pH testing e.g. hydroponics, horticulture, pools and spas, water treatment, beverage making, education, environmental monitoring, etc. Up to 3 points of Auto. calibration and 0 to 50˚C Auto temperature compensation (ATC), 0. 1 pH Accuracy with 0 to 14. 0 pH measuring range; Auto. recognition and indication of stable values improves repeatability, saving you the trouble of guessing when to manually hold measurement. PH20 comes with a complete kit of premixed calibration solutions (4.00 and 7.00), 4 AAA batteries, and a lanyard all in a portable carrying case. Smart Self-diagnosis, warning of incorrect buffer solutions and incorrect calibrations. IP67 water-resistant. Up to 2000 hours' operation powered by AAA alkaline batteries. The product is CE and RoHS certified, and is manufactured under an ISO 9001: 2015 certified quality system.

Brand: Apera Instruments


Special Feature: Waterproof


Color: Regular Kit


Age Range (Description): Adult


Included Components: PH20 Value pH tester kit


Outer Material: Plastic


Specification Met: CE, ISO 9001, RoHS


Display Type: Digital


Product Care Instructions: Hand Wash Only


Unit Count: 1 Count


Additional Features: Waterproof


Display Type: Digital


Power Source: Battery Powered


Number of Batteries: 4 AAA batteries required. (included)


Upper Temperature Range: 50 °C


Response Time: 5 seconds


Reusability: Reusable


LowerTemperature Range: 32 °F


Indoor Outdoor Usage: Outdoor


Battery Life: 2000 hours


Outer Material: Plastic


Product Care Instructions: Hand Wash Only


Color: Regular Kit


Style Name: Regular Kit


Unit Count: 1 Count


Item Length: 21.8 centimeters


Brand Name: Apera Instruments


Age Range Description: Adult


Included Components: PH20 Value pH tester kit


Model Name: PH20


Model: AI209


UPC: 858718006339


Global Trade Identification Number: 39


Manufacturer: Apera Instruments


Warranty Description: Two-Year limited warranty for the instrument, Six-Month limited warranty for the electrode(s).


Item Weight: 3.9 ounces


Part Number: AI209


Specification Met: CE, ISO 9001, RoHS


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Sep 22

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View our full returns policy here.

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Top Amazon Reviews

    • Highly recommend
Style: Regular Kit
Just as good as bluelab half the price. Very reliable and stable and easy to use. pH is on point
Reviewed in the United States on August 15, 2026 by Trenton Arnold
    • Best bang for your buck.
Style: Regular Kit
I love this ph pen with just a few complaints . Seems to be the most accurate I have used . This is my third one. I also just purchased the ac infinity ph pen which I swear is made by the same company but it has a replacement head. But it’s always a point and a half off compared to my two aperas that I double check everything with. So I’ll probably be contacting them to see what’s going on or taking it as a loss and sticking with these. For the quality you get I feel like price is fair . Just bought the tds too so I’ll be checking it out over the next few weeks. Be careful the glass bulb is very thin and easy to break when cleaning. My fault though. I was using the wrong thing to clean with and now I use old nylon paintbrush’s for watercolor and those stiffer bristles seem to clean very well. ... show more
Reviewed in the United States on August 15, 2026 by Justin
    • Love ir
Style: Regular Kit
“I’m really happy with this purchase! The quality is better than I expected, it arrived quickly, and it works exactly as described. It was easy to use right out of the box, and you can tell it’s well made. I would definitely recommend it to anyone looking for something reliable. Great value for the price!” ... show more
Reviewed in the United States on July 29, 2026 by Nancy Ramos rizo
    • Accurate and Easy to Use - But do you Really Need to Spend $50?
Style: Regular Kit
I bought this tester mainly to verify two cheaper ones I had already. I was just not confident the ones I was using were giving me accurate readings. When I tested them with calibration solution they both read slightly off one being higher and one lower. So I decided to spend the money on a higher end model. The Apera model seems to work very well and when tested in calibration solution is usually spot on. It has a nice LCD display which is easy to read during normal operation and is much quicker at determining the PH level versus the cheaper ones where you need to wait a while for them to stabilize and typically have much smaller and darker displays. That is the good news, however, the calibration procedure is a bit clunky compared to even the other cheaper ones I have. Partly due to the instructions which are very poorly written, hard to follow and provide contradictory information when it comes to things like storing the device. I understand it was made in China but for gosh sake, hire someone who knows how to speak and write in English to design the manual so it makes sense. In my application PH is very important so having more than one tester is not a bad thing. But it I had to pick just one and price was not an issue....then yes, I would chose the Apera model, but by a very small margin. Mainly because it appears to be a higher quality, well made device - even though the included instructions and funky calibration procedure hold it back from a five star rating. But in the end it is only slightly more accurate then the $10-$15 ones I already have. If the accuracy of the PH reading is that important to you and you want the best and do not care about spending $50, then the Apera is a fine choice. But if you are on a budget and are using a tester to check the PH of say swimming pool water, a cheaper model will work just fine. I would recommend getting two cheaper units from different manufacturers so you can check them against one another. You will spend about half of what it cost for the Apera. And as long as you occasionally test and re-calibrate them, you are better off with two cheaper models than the one more expensive one that does the same thing. ... show more
Reviewed in the United States on June 19, 2021 by E. A. Jacques
    • Accurate, reliable, and perfect for professional kitchen use.
Style: Regular Kit
Review Image by TC
Review Image by TC
I bought the Apera AI209 Value Series pH Tester for use in our professional kitchen, mainly to test the pH levels of barbecue sauces and hot sauces to ensure they stay below the required threshold for shelf stability. It’s been a fantastic upgrade from our old Dr. Meter testers, which were cheaper upfront but rarely lasted more than three months and were frustrating to keep properly calibrated. The calibration process with the Apera is a breeze. Unlike other brands that give you powder packets you have to mix with “clean” water (and good luck deciding what counts as clean), this kit comes with bottles of perfectly balanced calibration solutions; no guessing, no inconsistencies, and no cursing over cloudy mixes. You start with a solid, reliable baseline right out of the box. Readings are quick (usually within 5 to 10 seconds), and the included carrying case is surprisingly sturdy and well-organized. It's been dropped a few times already. I know this pH tester is marketed toward a wide range of uses, but for food safety applications in a commercial kitchen, it’s been excellent. It gives us accurate, repeatable results, and peace of mind knowing our sauces are safe and shelf-stable. ... show more
Reviewed in the United States on October 25, 2025 by TC
    • Excellent PH meter! Just Buy IT!
Style: Regular Kit
This right here is a key piece of equipment when growing anything, I bought the apera based on the review of 420scene on YouTube. I've had this for 3 months now, it does not loose calibration like my other meters. I do however calibrate once a month to be sure, and it's always on point! Just nice to to have piece of mind. I bought the regular kit, and ordered the storage solution separately, looking back I wish I got the big kit with stand and cleaning brush and extra fluids. The regular kit still comes with everything you need to get started. If your on the fence, just do it! It's better than spending a lot on the big blue brand and I'm glad I didn't and got this! Batter life is awesome, the casing is sealed and prevents water and nutrient solution from entering. It does have an auto shut off after 5 minutes, the overall quality it nice, it's git decent weight for handling, the screen is easily readable, only thing I would change is the LCD being lit up, there is not backighting. ... show more
Reviewed in the United States on April 5, 2025 by AvidCamper840
    • Quick accurate readings
Style: Regular Kit
Great unit with quick and easy PH readings.
Reviewed in the United States on August 14, 2026 by Amazon Customer
    • Wish I'd known this. Great, if it works, but it DOES NOT MEASURE EMPTY WATER.
Style: Regular Kit
This thing is advertised to work for general liquid solutions. Unfortunately, be aware it does not read water. Yeah, you read that correctly. You need enough stuff IN the water, or it will not read the water. I use reverse osmosis water for my plants, and it is "empty." I add nutrients to it, but it takes a LOT of stuff in the water before you get an accurate reading. To make matters worse, it will not tell you when it is doing this. You will have no idea. I suddenly thought there was something wrong with my R/O water causing it to be extremely high pH. No, it was not the water; the water was still the same old 5.5 pH it always was, but the pen COULD NOT read it properly and was telling me 8 pH. THERE IS NO MENTION OF THIS anywhere before you purchase it. It is not mentioned in the instructions either. Therefore, I trusted the meter (which works phenomenally otherwise) and completely ruined months of work. Additionally, I often want to water my plants with water that is at the right pH of about 6.5, but does not have ANY nutrients. This is common, called a "flush," because you don't want to keep feeding nutrients to plants that don't need it. Well, you can't measure water with this, so I can't do that. For the high price, it works great, but it does NOT work in all situations, and they make little effort to warn you of this. Now I have to buy one that costs twice as much??? This is stupid. So now I am left to bumble around confused using both this and the pH strips I was trying to get away from. Now I need yet another unit that will measure empty water. I had a $5 one that did it, which I threw away once I got this, thinking I would no longer need it. This seems absurd to me. I guess I am one of the few people using reverse osmosis water or something? I think I deserve a refund or upgrade to a version that will WORK, but I doubt I'll even get a response, and if I do, the responses will just blame me instead. My ignorance isn't my fault if you don't make an effort to alert me before purchase. And don't tell me to do more research. I DID research. ... show more
Reviewed in the United States on February 28, 2021 by JDW

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