VIVOSUN Digital pH Meter 0.01 Accuracy Pen Tester for Water Hydroponics | ±0.01 pH Accuracy, ATC, Auto Calibration, Backlit LCD, Memory, Compact, UL Certified, for Hydroponics Aquarium Pool Drinking

This is the second of these PH meters I've purchased. There are a number of negative reviews, so I was a little concerned but went ahead and order one. The first meter calibrated easily and (apparently) accurately. I used the three point calibration, then tested my fish tanks and compared the reading to the drop type ph test kit I had been using. It was spot on as close as I could tell with the test kit. I used the meter for a week, every day on several tanks as I changed the ph. It tracked these changes as I would have expected it to. It worked very well for me so I ordered a second PH meter. (I have fish tanks in two locations.) I then used these two meters side by side. They vary from each other by 0.10 points. The second meter did not calibrate as easily as the first, and the calibration was off slightly. I will try recalibrating, but it's as accurate as I need now. I'm very satisficed with them and would recommend.

Although it may be a little delicate to calibrate upon first time using. Insure solution temperature is ~75 degrees F. Measure out 250 ml distilled water. Insert the meter into a cup pour into another cup until you reach the line on the meter. Turn meter on holding down the calibrate button for 5 seconds then release. Press Cal button one more time. I did not get a display showing "cal" like some of the YT videos. This generates confidence in the meter concerns. However, I had a lab tech at the university check the calibration in a buffer solution of 7.0 and the meter showed 6.97. First pH meter that works and provides accurate results.

First one arrived and it worked for about 2-3 days and then the screen started displaying nothing but wacky symbols even after leaving it off for a long time. Got an exchange from the seller and the new one seemed to work fine but started giving questionable readings. I set this device aside for a while and just returned to test it and tested it numerous times on multiple water sources. Water is supposed to be a pH of 7. It started at 8 and then slowly and continuously just kept creeping downward until several minutes later finally setting on around 4.7 each time. That's absurd. That's somewhere between a tomato and black coffee. And no, I don't live in Flint, MI. There's nothing wrong with the tap OR bottled water I tested it with. Additionally, I noticed that the device they sent me as the exchange had an LPN label on it - which for those who aren't aware is a label indicating that an item was a pull back or return. Amazon puts these on items that get sent back so that they specifically are not to be sold again. Amazon usually covers the UPC or other barcode for this exact reason. I did notice it when it arrived but it seemed like it was brand new so could have been an overstock return from their FBA warehouse at some point. But they sent me an item that Amazon specifically would NOT allow to be sold/resold on it's own website.

Item Reviewed: VIVOSUN Digital pH Meter, 0.01pH High Accuracy Pen Type pH Tester for Hydroponics, Household Drinking, Pool and Aquarium, Yellow, UL Certified ℹ️ Summary I picked this up for pH balancing water that I use for my indoor grow tent and it has worked great for that purpose. For $10 at time of order, you’re getting a meter from a reputable brand that won’t break the bank and does exactly what it’s supposed to do. Included in the package are a nice plastic storage case, extra batteries, and a set of pH calibration buffer powders (6.86, 4.00, and 9.18), which was a nice touch. Calibration was quick and easy and I’ve only needed to recalibrate about once every 3-4 weeks. Readings also seem accurate and consistent. My only real complaint is the build quality. It definitely feels made from cheap plastic and while the buttons are clicky, they still feel a little flimsy. Overall though, I’m happy with this purchase and can comfortably recommend it as long as your expectations match the price point. ✅ What I Like - Low-priced. - Gets the job done. - Comes with a decent plastic storage case. - Includes pH calibration buffers (6.86, 4.00, and 9.18). - Comes with an extra set of batteries. - Readings seem accurate and consistent. - Calibration process is simple. ❌ What Could be Better - Build quality could be better. - Feels made from cheap plastic. - Buttons feel a little flimsy despite being clicky. Final Verdict | ⭐️⭐️⭐️⭐️☆ Here is how I rate items: 5 ⭐️ = Completely exceeds expectations. 4 ⭐️ = Works well with minor concerns. 3 ⭐️ = Does the job, nothing special. 2 ⭐️ = Some things work, but lots of issues. 1 ⭐️ = Didn’t work well, not worth it.

Very easy to use and calibrate returned on that was bad and they replaced it in one day!!!!

The VIVOSUN digital pH meter is easy to use and gives quick readings, which is convenient for basic testing in hydroponics, drinking water, or pools. The pen-style design is compact and portable, and the display is clear and easy to read. However, the accuracy can be inconsistent unless the meter is calibrated frequently, and the readings may drift over time. Build quality feels somewhat lightweight, and for more precise or professional use, it may not be fully reliable. Overall, it’s an acceptable 3-star product for casual or occasional pH testing, but it may not meet expectations if you need high accuracy or long-term stability.

I can honestly say this little pH meter (black Vivosun) has exceeded my expectations. For such a low price point, I figured there would be considerable issues with sensor drift requiring constant calibrations however this little guy has always been within .1 pH when checking prior to the calibrations I have periodically performed over the last few months. Proper rinsing and storage as well as frequency of use are also important factors when maintaining accuracy with a pH meter however the quality of the sensor is also part of the equation. With that being said, this Vivosun pH meter appears to be well made. I would always recommend periodic calibration of a pH meter if you are relying on its accuracy regardless of the manufacturer. The probe is easy to use and easy to rinse after use eliminating any hassles and the removable probe cover provides protection during storage. The readings quickly stabilize which has also streamlined my testing process. Overall, this has been a great value and I would recommend especially if on a budget.

Works great

La calibration est simple. Par contre, par rapport à une sonde témoin, il est extrêmement lent. Il faut compter presque 10 minutes pour que le pH final soit affiché. Il faut donc le mettre longtemps pour à avoir le bon pH. Après 6 mois et une utilisation par mois, il deconne complètement. Mauvaise qualité

Macht seine Aufgabe gut.

Arrived not working, tried replacing the battery but no joy so sourced an alternative

calibration is hard but when it's done it's good

Works great but do not like that have to calibrate it