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.

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.

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.

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.

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.

Forgot to right review but very good cheap devices I mix my plant food with them they work well