VIVOSUN PH Meter Digital PH r Pen 0.01 High Accuracy Water Quality r with 0-14 PH Measurement Range for Household Drinking, Pool and Aquarium, with ATC, Orange

Works very well.It’s easy to use.It’s easy to calibrate.It has an on and off switch!This is the good one on the cheap.

Ordered this as i had a grow tent emergency, Worked once and now it doesn't work at all, it turns on and reads PH16, unable to calibrate. Spoke with customer service they said they'd look into to a warranty, we shall see, however had I had known it was problematic I would have spent a bit more and got a more reliable product. and with the delays for warranty etc, my PH problems will likely get worse as i can't measure.

I’ve only had this for 2 weeks and I’ve had to recalibrate 3-4 times. It won’t hold calibration. I was excited to get this bc the one I had before was the older blue model (can’t remember the brand). Anyways, after fighting w this thing since I received it 2 weeks ago, today it started being so weird. Numbers were flying all over the place. I thought I’d calibrate and see if that would line it out AGAIN... the pictures show the meter in the 6.86 solution. It threw decimals out the window and started just going crazy. It wouldn’t turn off. I finally! Got it to turn off. Turned it back on and it wouldn’t ready anything except 16.00. It would not change. And it’s sitting in 6.86 in that pic also. If you buy this, I hope you have better luck. Or patience. Or maybe you don’t really need to know the ph after all lol now I have to wait another week for a new one bc I just started my refund on this one. If it was me, I wouldn’t do it. Try your luck with a different one. The blue one lasted longer than this. It was crap too but it lasted 6 months. Ughhhh...Edit: instead of just returning the other one, I had them send a replacement. This one is trash too. I just calibrated it yesterday and it’s reading my tap (which is usually around 7.3-7.5) at 8.8. That’s how I can always tell when a pen is way off. I also have a backup pen I’ve been using just to make sure. If it was close, I’d still try to use it. But floating 1.5 in ONE day is ludicrous. I’m sending it back for good this time. Guess I’ll try a different one. I do not recommend this one.

Super simple to use (as are all of these), but the accuracy is questionable at best. Using a 4.0 and 7.0 Standard at the lab at work, this read 4.0 and 7.6, respectively. The calibration is crude and requires out of normal standards for (hydroponics or aquariums) and needs de-ionized water that most home users will not have access to. The standards needed are 4.01, 6.86, and 9.18 which are more expensive to attain. Even after calibration, the accuracy wanders quickly. Unfortunately, that didn't matter too much as the bulb shattered after about 2 months of use. The battery included did last longer than the meter, though...

My readings are all over the place. Doesnt hold a calibration. Might as well toss in the bin.