VIVOSUN Digital pH and TDS Meter Kits, 0.01pH High Accuracy Pen Type pH Meter ± 2% Readout Accuracy 3-in-1 TDS EC Temperature Meter for Hydroponics, Pool and Aquarium, Yellow Blue, 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.

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.

The TDS meter works very well, especially considering the low price — it gives quick and reliable readings. However, the pH meter takes a bit longer to stabilize and provide an accurate measurement. Overall, it’s a useful and affordable kit for basic water quality testing, but be patient with the pH readings.

Vivosun Digital pH and TDS Meter receive a 5-star rating because of the customer service, and the products. The pH meter was not working when we received it. I contacted Vivosun and they offered a refund or replacement. I went with the replacement and received a new pH meter the next day. Both meters are working, now I just need to adjust the pH in the water I am giving my herbs so we can all be happy.

I have a scientific grade PH probe that has been in continual use on a 65 gallon discus tank for 6 months and it was time to recalibrate as part of routine maintenance. After 6 months of use, probe had barely drifted. I used PH 4.0 and PH 7.0 calibration fluids. Probe was spot on with the 4.0 and read 7.1 with the 7.0 so it only needed a very minor adjustment to bring it back into perfect calibration. I used this probe as a comparison with the VIVOSUN. The VIVOSUN readings straight out of the box were pretty far off. Measuring the PH 7.0 solution, the VIVOSUN reported 7.6. Measuring the PH 4.0 solution, VIVOSUN reported 3.65. I calibrated the VIVOSUN using the provided powder for all 3 PH solutions provided as this should provide the most accurate readings per the instructions. Immediately after calibration, I poured fresh 4.0 and 7.0 solutions and the VIVOSUN results were at least .5 off in both directions. Poured fresh solution AGAIN (after rinsing probe in RO water) and once again results were way off (but different from the results it just reported from the first fresh solution pour. I then compared with test strips and the test strips matched the results from my scientific probe. In short, do not rely on the pH meter and I would go so far as to say you need to throw it in the trash ASAP. The TDS meter is also flawed. There are 4 modes of display, according to the instructions whichever mode you choose will remain the default until you change it.. (e.g. Power it off today and tomorrow when you power it on, it should default to the mode it was in when it was powered off.). It does not do this. Not only that but in the middle of taking a reading, it will just randomly switch from measuring PPM to EC or from Celsius to Fahrenheit. I don't have anyway to validate the EC or PPM readings but judging by what I can validate, I would not trust it in any way, shape or form.

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 picked up this set to help me get my Kratky mason jars tuned correctly for the herbs I’m growing indoors; mostly oregano right now, plus a few other experiments. For something this inexpensive, the meters have been surprisingly useful. I looked up the pH and nutrient ranges my herbs needed, mixed my A+B solution, and then used these meters to tweak things until everything landed where it should. The readings have been consistent so far, and they’ve made it a lot easier to keep my jars in the "happy zone" instead of guessing and hoping for the best. If you’re getting into simple hydroponics or just want a straightforward way to check your levels, these do the job without any fuss. My plants certainly seem to appreciate it.

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

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

I bought this set mainly to check the conductivity of my LC coolant in my Ioniq 5. The items arrived quickly and safely in a solid box. It came with full instructions and even an extra set of batteries. I checked the TDS meter using tap water and got an expected reading of 56 (pure distilled water would be closer to 0) us/cm. I am very pleased with the performance and the value. Highly recommended!

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.

Al tratar de calibrarlo en la solución 6.86, se activaba el calibrar pero tardará mucho parpadeando y cuando paraba aparecían las letras, Err y de ahi no pasaba..