DuvinDD 18 Pack pH Calibration Solution Powder 6.86/4.00/9.18, pH Buffer Calibration Solution Packets for Precisely Calibrate pH Meter, pH Tester Calibration Powder Packets

Works exactly like it should product seems to be good for accurate calibration for a good price.

This pH calibration solution works as expected. Shipping was fast. The powders dissolve easily and I was able to calibrate my pH meter without any issues. The seller is also worth mentioning. They were helpful and responsive when I had a question. Good customer service is always a plus. Overall, a solid product and a good buying experience. I would definitely recommend.

These are what they are. Calibrated my cheap pH meter for brewing and checking my mash pH.

Works as expected I hope but like others have said the crystals don’t dissolve very quickly for certain ph. I just mix and then come back a half hour later to mix again

I like using these powdered calibration packets, they are simple and straight to the point. You don't have to throw them out after 30, 60 or 90 days like the liquid calibration solutions tell you to. All you do is pour each packet into a cup with 250ml of distilled water, make sure its dissolved, insert the pH pen and hit calibrate. BOOM! Calibrated. Easy peezy, lemon squeezy! Highly recommend these packets.

Using a powder buffer solution is more tedious and annoying than a premixed solution, but this does a great job. The only issues I had was when the water temp was too cold for the powder to dissolve properly.

Works great Thank you!

This is a nice set to help keep my ph meters calibrated. Would buy again.