LLC - AI1109 227g pH Calibration Buffer Solution Kit (pH 4.00, 7.00 and 10.01), plus 3M KCL Storage Solution for pH/ORP electrodes

It was accurate gave me right results

If you have one of Apera PH meters and you are using it because you know it's very accurate then you need to have calibration solution on hand and use it! This takes all of the guess work out of it. Pairs great with the PH60 to keep my plants living in a comfortable soup knowing they are able to get the nutrients they deserve. As a bonus you have to have the KCI liquid anyway to store the meter. The only crazy thing to me is that when you spend $100 on a pH meter that comes with the smallest bottle of storage solution practically making you have to purchase this right after spending a small fortune on the meter feels kinda predatory towards your customers. Why not include a bottle the same size as the calibration solution included there would be plenty of room in the case for it. I get it is just another source of revenue for the company. I'll still buy it because I trust it.

i have multiple pH meters for my two large turtle and fish aquariums and this was great at helping me recalibrate them because they hadn't been used in a while. I am done with trying to use pH water test strips. Nothing beats a digital gauge. Easy to use and store and bottles were brand new and unopeneed. I'm able to maintain .1 accuracy of pH in my tanks now. Also never again will I use the pH powder packet kits. This is so easy!

I used the 4.0 and 7.0 to calibrate my ph controller and ph digital hand meter. Works fine.

Best product that we’ve used to calibrate our pH meter.