Needed calibration out of the box. I have professional chemistry solution used to calibrate meters that cost a lot more than these cheapos. used my ph 4/7 to calibrate this meter because mixing a solution out of a packet for a none standard way to calibrate the meter is just dumb...

I am using this meter for wine making. I looked for a meter that advises using ph 4/7/10 to calibrate their meters. All the meters that advise using a calibration solution that is not subject to human error cost too much to justify the cost on such a small hobby project. calibrating a meter by mixing a packet is super dumb if you really need accuracy. ph 4.01/7/10 solutions are not subject to human error like mixing a packet is. Any meter company advocating using a packet that needs to be mixed loses a lot of respect in my book.

If you have the money/need to justify a better meter, hanna instruments meters are probably something you should look at. I am buying this meter under the assumption that I am probably going to have to throw it in the garbage sooner than later.

Meter works but as a first time garden grower I learned a hard lesson with PH levels and accuracy. I made the poor assumption that this meter would come calibrated within a reasonable range and even though it comes with a way to perform a calibration if you want to I did not. Fast forward several weeks and many of my plants look smaller than they should, started showing signs of curling leaves (upward) and tips of leaves browning. Kept checking PH and it was in range so wasn't sure what was going on. To be safe I bought some PH strips and lo and behold my PH was really at 8.5 even though meter was registering closer to 6. So my plants were in nutrient lock out as a result. :( If had a do-over button I would have bought both the PH meter and strips at the same time, calibrated the meter on day one and always checked PH levels using both meter and strips to be confident of readings. So lesson learned. I deducted a star from rating because the calibration was so extremely off and many people are prob not going to calibrate unless there is a giant sticker on device that says you must do it as first step.

Update: Company was quick to contact me about the product, admitting that sometimes items can slip by QA with issues. They offered me a refund to make up for the trouble - as I had already purchased a different item so I could keep an eye on my hydroponic reservoirs. While this product is not for me, I will certainly recommend that folks at least give it a try since the company behind it definitely stands by their promises of satisfaction.

Literally took it out one time to test pH in my hydroponic reservoir, the glass bulb on the end shattered shortly after removing it from the solution. Cannot recommend at all and hate that I wasted money on it. The claims of durability are clearly overblown. Additionally, even if it had not broken, the top where the switch is located is NOT securely fastened to the rest of the pen, it just falls right out with batteries and all - only held in place by two wires.

Easy to use, accurate. I tested along side the kind you put water in a tube and ph drops and readings came out very similar. Use it for hydroponics and testing my drinking water.

This ph meter is handy, easy to use, inexpensive, and accurate. If you have fish tanks, using a pH meter is much easier and more accurate than using test drops or strips. The pH of my tap water varies and normally too high for my fish tanks. When I make weekly partial water changes on my tanks, I use this meter when adjusting the pH of water than I'm going to add to the tanks. By always adding water than is 7.0, I don't have to worry about the fish being shocked by large changes in pH. Being able to quickly and easily test the pH of a tank is a very handy as an indication problems with water quality. If the pH of a tanks shifts rapidly, it is an indication that something is wrong. Changes in pH also make it harder for fish to cope with other water problems such as Ammonia, Nitrites, or Nitrates. By checking the pH with this meter and the TDS with another, I can quickly check all of my tanks. If the values shift dramatically, then I know that I need to get out my test kit for test for all of the other stuff, and do a partial water change.

Unless you pay 10 times as much or more for a laboratory quality meter, all of these affordable pocket-pen metes like this one will need adjustment for drifts in the reading over time. I bought a kit at the link below with test solutions of known pH, which makes it easy to know if the meter needs adjustment occasionally This meter is easy to adjust with a screw on the back.

https://smile.amazon.com/gp/product/B0063MVU5S/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

About once a month, I simply dip it into a solution of known pH, and adjust the screw slowly if needed until the display shows the correct pH. Other meters that say they are "auto-calibrating" are anything but automatic. They require you to have test solutions of 2 different pH, normally 4 and 6.86. Finding test solutions of the required pH is often difficult or requires messy mixing of exact amounts of powers and distilled water. The auto-correcting ones then require complicated procedures of pressing and holding buttons while you dip the meter in test solutions and clean the meter between in distilled water between each test solution. It is time consuming, messy, and confusing.

Simple meters like this one with an adjustment screw are much, much easier to test and adjust when needed. You simply dip it into a test solution of any known pH, and then adjust the screw if needed until the display shows the correct pH for that test solution. Adjusting one like this with a screw adjustment is no harder than moving the hands of a clock for day-light-savings time, while the "auto-calibrating" meters are more comparable to filing a long-form income tax return on paper without a calculator or PC.