I have used so many different pH meters and honestly, unless you make a religious habit of washing them with distilled water after every use, they wont last long. With that said, there are definite differences in quality, but this is not one of those devices that go with the phrase “you get what you pay for”. I have had expensive ones and generics and I could safely say that unless you have a full scale grow op, you do not need a high end one.
So first, Ill start with the toothbrush case shaped meters. These are both generic and official brands and they’re junk.
They need to be calibrated almost every other week and readings get thrown way off when water dries up on the sensor. This happens with all meters, but its way more obvious on these and I have gone through 2 in less than a cycle. The other downside is that they are not waterproof, so one drop into water and it’s RIP.
What the pH!
Now the other end of the spectrum is the high ends. Brands like Apera make entry level ones for about $80 bucks. Honestly they are basically the same as mid priced ones. The ones with the probes usually cost more than $200 and measure more than pH and I find these are very useful in commercial settings. A small home grow op would not find enough value to find this worth it.
Lastly, is the mid range meters which you can find around $35.00. These are by far my favorite and the mechanics are identical in both Generic and Name brand ones. They can measure pH, TDS or total dissolved solvents and temperature. TDS can be used to set the ideal nutrient levels for your plants at different stages of their life:
These mid range meters are also waterproof with a IP67 rating and I find mine more reliable and quicker than my Apera. I still calibrate it every month, but I do this more as a precaution.
VIVOSUN ph Meter, Bluelab PENPH, Apera AI311, Dr.meter ph838
Mid-Range with ip67 with built in TDS meter is the best. Search "3-in-1" and you will find the best ones in my opinion. Way more reliable than others.