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

They seem to be working okay although I don't like how they have to be calibrated. But they do work.

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.

Takes forever to read but good value for the price

I've found these to be very accurate and easy to use. So far I've used it to test our tap water, filter water, aquarium water, and spring water on our land. The ease of the devices is really top notch. I'd highly recommend to anyone interested in a quick look at true water quality.

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.

First, the good things.The EC meter is pretty good all around. It's easy to use. Measurements came up within acceptable ranges and was very consistent.The pH meter is sort of easy to use and does get you in the right general range when calibrated. Results are fairly consistent. Even if you can't get final results instantly, you can at least tell if something is acidic or basic fairly quickly.Now for the bad.The backlight on the pH meter only stays on for a few seconds and there's no backlight button to turn it back on. You just have to turn the meter off and then turn it back on. It might not be an issue if it weren't for the fact that the directions tell you to stir the mixture you're testing and wait about 30 seconds for the reading to settle down, which means the backlight is already off by the time you need to read it.The EC meter has no backlight at all.The pH meter is only vaguely accurate despite the claimed accuracy and the decimal places available. It generally takes the full 30 seconds for it to actually settle down, which means it's not a very quick test. And when it's finished it's only approximate to what the value should be.The meters aren't built to be submerged past a certain point that isn't clearly marked on the actual meter itself and is actually really close to the point you need to submerge. If you submerge past that point, the manual states that the meter may break.All in all, I say you get what you pay for. It's a fairly cheap product that provides a moderate level of accuracy and nothing more than the bare minimum.

These work great for my hydroponic vegies. Easy to use and a great price.

Easy to use and very accurate.