pH Buffer Calibration Solution Kit 2-Pack — one pH 4.00 (red) and one pH 7.00 (Yellow), Each 500 mL (1.06 Pint) — NIST Traceable Reference Standards for All pH Meters

Price was right. Works to balance my spa for correct pH range

I would recommend this product

Will be a future customer for sure!! This solution is very Accurate, have compared it to other solutions and there is no comparison if you are looking for accurate solution to calibrate your Ph meter.. FYI..if you are using a Bluelab PH pen made in the last year or 2...Throw it away and do not trust it!! Lots and lots of people complaining about inaccurate readings and the pH Pens going bad and will not calibrate...Then bluelab not standing behind their products or their warranty!!

Works as advertised and is very accurate.

The pH meter and the test results are useless without checking and calibrating your meter.

I have used testing calibration solutions like this for many years and these products are a great value for the money. Plus, they come with certifications traceable to NIST!

Products made August and October 2018 with expiration dates of August and October 2020! I own and operate a small cheese plant so don't use a lot of product. Nice to know it won't expire before I use it up. Rapid delivery as well.

I got this to recalibrate my milwaukee ph probe after calibration i noticed the ph values where low, lower than before i calibrated so instead of jumping to conclusions on having low ph in my reef aquarium i ordered milwaukee ph solutions and there was a big difference in numbers so with both calibrations i used an alternate hanna ph checker to see witch of the two calibration fluids where correct and milwaukees calibration fluid turned out to match the hanna ... i dont wanna say this company's fluid is bad cause i do know there are factors like age that can throw the ph off of the fluid but in my case the fluid was not a true 7 nor a true 4