VIVOSUN Digital pH Meter, 0.01pH High Accuracy Pen Type pH Tester for Hydroponics, Household Drinking, Pool and Aquarium, Black, 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.

So I bought this set wanting to try out actually tracking and adjusting my pH and EC of my nutrients for my little indoor hydro-farm. Like most people, I didn't want to spend a lot on my little hobby so I figured I would give this product a try as I actually enjoyed some other Vivosun products. I'll start with the TDS/EC Meter. It is actually decent and appears to be pretty accurate right out of the box. I've used it for a little while and it remains to be acceptably accurate so far without any issues. Good to go, this one I'm pretty happy with and will continue to use at least for now. Next I'm moving on to the problem child, the pH Meter. Wow. Where do I begin. I started off trying to figure out how to calibrate this little thing as the instructions drastically varied from all the calibration videos available online for it. Maybe they changed the method but once I figured out how it wanted to be calibrated I went through the steps and all was good. I tested it a number of times using various testing liquids and it was pretty spot on (at least within acceptable limits for my hobby, not anything that needs to be precise though). So I mixed up some of my nutrient solution, cleaned the pH and TDS meters as advised to in the manual and put them away safely. Fast forward 1 week, I pull out the pH meter and dip it into a cup of distilled water and it tells me that it has a pH of 10.3! Far from the value of 7 I was expecting to see. So I pulled out my other pH balanced liquids to test and every one of them was extremely off from what it should be. It completely lost ALL calibration after one use, and one week of storage. I'm sorry but that means I need to calibrate this thing every time I turn it on? And they only supply you with one set of calibration powder that isn't to be re-used? Absolute and complete garbage. The calibration costs for a year would be well into the hundreds a year for a $10 meter! Absurd. This is a product you should definitely skip buying. Buy yourself a 14-sided dice and give it a roll, it will give you a more accurate guess on your pH level than this thing every will. I would return it, but I was not thinking and threw away the packaging already.

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.

An inexpensive yet reliable meter!

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