Digital pH Meter, 0.01pH High Accuracy Pen Type pH Tester for Hydroponics, Household Drinking, Pool and Aquarium, Yellow, UL Certified

After reading several reviews on this and other similar models I decided on this two pack PH and TDS. I recently installed a reverse osmosis under kitchen sink with a tds digital display and wanted another way to check its accuracy along with what ph the RO water was putting out. Item arrived quickly and after reading instructions I decided to give it a test. Batteries were already installed and additional batteries were included so that and they both were already calibrated so two pluses from the start. I filled a glass with reverse osmosis water and another from bathroom sink. Tds for bathroom were 107 compared to RO water of 9. This is the same reading my RO system shows so I assume its pretty accurate. Next I tested the PH. Ro water was higher than bath sink water but this units numbers jumped around a bit. Although the numbers did not display steadily i was able to get a good reading and am pleased with the results. For the price I find the two units a great bargain and much better than the water test strips I was using. After my initial tests I highly recommend these products as they appear to be accurate and easy to read.

The ppm meter comes ready to use, the pH meter needs to be calibrated before use with the provided materials. It works well and is pretty fast.

I am an analytical chemist: TDS measurements are low at 10-15%. I checked TDS using 745 mg/L KCl standard at 1x and 10x diltion with % recovery of 90 and 85% respectively. Standard was checked with ISO 17025 orion TDS/EC meter at 98% recovery using EC. Will update with pH readings. I have not calibrated it. For the price it is great especially if you just need a ball park estimate. Nice that the TDS comes precalibrated but I will be recalibrating mine because of the %recovery issues.

My husband originally purchased this set last month so we could keep a closer eye on the water quality for our plants. We are on a well, so having a consistent way to check the water quality is essential. These meters have been surprisingly accurate and very easy to read, which has taken all the guesswork out of our routine. One of my favorite features—especially as someone who isn’t a pH testing expert—is that the two meters are different colors. It sounds small, but having them color-coded makes it so much easier to grab the right one at a glance! In terms of functionality and sturdiness, the pens feel well-made and durable. The caps have a tight seal, which is important for protecting the sensitive electrodes from drying out between uses. The digital screens have great color accuracy and clarity, making the numbers pop even if the lighting in the greenhouse or kitchen isn't perfect. For the price, you get a lot of accuracy and peace of mind.

The pH meter ended up being basically useless. I carefully followed all instructions. It took a lot of time and frustration to successfully 3-point calibrate it. After calibration it seemed to be partially accurate but it would take 2+ minutes to provide a reading. Even then, it would start about 2 points above the real reading then slowly keep drifting downwards at a rate of roughly 0.01 per 1-2 seconds. It would never “land” at a reading. After a week of use I gave up on it and just went back to using chemical pH tests because those only take a fraction of the time to get a ballpark reading. The TDS meter was a little better. As I said before I followed all instructions carefully regarding usage and proper storage. For the first month of regular usage (used 1-3 times per week) it worked great and exactly as expected. Then the temperature readings became unreliable. I have other digital thermometers to compare it to and this device was consistently off by about 5-10 degrees fahrenheit which made it useless at that point. The TDS portion of the blue meter seemed to be accurate and mostly worked until the end of the 2nd month. Then it would randomly behave strange. I would test the same sample of water 3+ times over 10 minutes and the ppm reading would fluctuate by 10-40 ppm. Or sometimes I would test two samples of water from my fish tank taken about 24 hours apart. It would read out exactly the same as if the meter was “frozen”. I know that isn’t accurate as the 2nd sample would be taken 24 hours later after a fish feeding and a plant fertilizer dosing. So it’s highly unlikely that it would give an identical reading for the 2nd sample.

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.

Works great, easy to calibrate. Good quality, feels durable.

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.

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

Really useful, I think the price is spot on and they have helped remove some of the guess work when it comes to pH and ppm

Great product

TDS meter are working fine but for the PH meter I personally don’t arrive to fully calibrate it as all the time I do the PH 7 then PH 4 and when it’s arrive to do PH 9 it’s return to PH 7 so impossible to complete the calibration.

Works well