Biopharm pH Calibration Kit (2) 8oz Bottles pH 4 and pH 7 Buffer Nist Traceable Reference Standards for All pH Meters

Glad I settled on this one instead of another. I chose this one because of the reviews and that it looks more professional than one of the certain leading brands. Also, there were no complaints about packaging on this item. The bottles are really sturdy and sealed very well. They also come in individually sealed bags inside of a protective cardboard box with the hand-signed lab paperwork. It was pretty much a no-brainer. Worked perfectly to verify calibration of my El Cheapo $10-range pH meter (the generic yellow one you see everywhere). Verified it was calibrated correctly. I will be using this from now on to calibrate instead of powdered formula. When using, make sure that the solution is at 77°F when you're calibrating. Also, take note of the temperatures on the side of the bottle for different pH readings. Mine was too warm so after I poured it into my container I placed it on top of an ice cream carton for a few minutes with the thermometer in it until it was the correct temperature. If you need to warm it up I recommend putting the container in a bath of warm water. To test the meter, I cut a small (clean) ibuprofen bottle in half and put around a tablespoon of solution in there, just enough to cover the electrode. I did this to conserve the solution by using the least amount possible and it worked great. I am confident that this is working correctly because it verified what I already thought was true.

Great seller as products arrived far earlier than expected and decent sizes for calibrating my PH meter

I am a home cheesemaker and one of the things you need to pay attention to when making cheese is the level of acidity of the cheese as it is being made. For that, you need a pH meter and therefore you need to calibrate it on a fairly regular basis. That is where this product comes in. These are certified calibration solutions that you can use on your pH meter to make sure that its readings are reasonable. The product is very simple to use as the bottles are clearly marked and the liquids are colored so you are not likely to confuse the 4.0 with the 7.0. However, given that pH meters do not need to be recalibrated all that often, and that I do not make tons of cheese daily, the quantity of fluid that came in this package will last me for many months - probably far beyond the certified calibration date on it - which is a shame.

This stuff is good enough for professional hydroponic use for any size system. I have a cheap PH meter and a rather expensive one both and it was right on the dot with both. This will probably be my new choice brand from here on out. It's affordable and and accurate to the specific point which is great because there really is no room for error. Comes nicely packaged and contains a report on the fluid from the company. Easy and affordable pro grade, doesn't get much better. 5 stars. *If this helped you could you let me know by hitting the Like button? thanks!*

Seems to be a little low on the 4.01 buffer. Maybe a weak bottle?