pH and TDS

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.

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.

Accurate, it comes "pre-calibrated" for accuracy, though they also include 3 little foil packets of buffer powder to re-calibrate. But the 3 packets are for different pH levels. You can do 3 calibrations for 0.01 accuracy, but I would have preferred 3 packets of the pH6 buffer.

This simple product is accurate for my needs checking the pH of my canned goods. Calibration is easy and these are accurate. Fun to test the tap water! Great value and nice quality. This fits nicely in my drawer, haven't used the blue EC meter yet.