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

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.

Was actually surprised how well this works. It's cost effective. Easy to clean. Easy to calibrate and use. Very durable. Lasting me a while. Doesn't break.

Good for low budget testing. However you have to use packets of calibration powder. Not super convenient if you leave it in a drawer for a couple months to a year at a time. But it did seem to test and show results very well.

Spent 30 mins in calibrating , repeatedly , and still getting 14.00 on the reading in the air. Not trusting PH reading because of this. Nothing on the instructions explains why I’m getting 14.00 in the air ? Waste of time , just get old school PH strips , and you will be done in 3 seconds.

This is a good buy and easy to use. Mix the reagent with 1 cup water and calibrate with one button. Read my pool pH with one button. I lost my pH probe exactly like this and replaced it with a new one.

Freshly calibrated, this meter works fairly accurately (within .2-.4 of other sources I trust. I mean, really, for well under $10, it’s bargain! HOWEVER…There is a reason the instructions say to calibrate daily, before each use. After using it about 3 times, in various solutions I found it to be 1.5 units off! But once recalibrated, the circus was back in town and it once again gave accurate readings. But I’m just not willing to go through the calibration hassle before using each time. I even tried a trick a buddy should me where you stuff a tiny bit of cotton, torn off of a ball, way in the back of the lid and very slightly moisten it (6-8 drops?) with distilled water; this is suppose to keep the glass reading probe very slightly moist and therefore help keep it better calibrated.If you’re after accurate readings, and are on a budget, and are willing to pay for extra calibration powder packets, and do the calibrating before every use, this meter might work for you.I returned it and went back to my Biopharm droplet test kit—pretty accurate and reliable (General Hydroponics also makes a good droplet test kit, but not with the .5 increments that the Biopharm reads at).

Easy to use nice instruction to guide you through setup and then just hold it in your tank and in no time it gives you your PH reading so your fish will be happy

Worked okay for about a month. It would take a very long time to count down to a pH reading when exposed to an acidic solution, so long that the device would auto power off. For $8, hard to complain about that, but now after about a month, it just displays 14 all the time. Tried all combinations of button push and hold, batteries, etc., can not get it to work. Ended up buying the Yinmik meter for about twice the price, it is much faster reading and waterproof to boot.