Review on Accurate Multi Parameter Calibration with Apera Instruments AI413: Maximize Precision and Efficiency by Corey Krull

I received two of these devices and a special probe directly from Apera a while ago to compensate for the error problem. It turned out that the expensive probe was not needed. It was the counters themselves that both had the same issue that couldn't be resolved, similar to what others have reported here. We struggled from the start and struggled with them until we put them aside and borrowed Oakton from our sister lab. Eventually I got a call to Apera and they started questioning me and asking me to send them all possible proof of purchase. Suffice it to say that these devices are rubbish and their customer service leaves a lot to be desired. I just bought an Oakton 450 and it works perfectly. Not to mention that their customer service has been second to none over the years. Our company has similar Oakton devices that have worked flawlessly for many years, but I tried to save a few bucks by purchasing Apera devices and regretted it. I will never buy an Apera product again. Oakton costs more because they make quality products. Don't skimp on essential lab equipment.