Review on 🔍 Optimized Search-Engine Friendly Atlas Scientific Calibration Solution 4.00 by Phil Casey

I have been ordering from this manufacturer for several years. Would give five stars so far. The last batch came gave me some fun calibration curves on my Orion 250A (pretty good instrument). None of my other pH meters could calibrate this batch (failure). Went back to more expensive NIST traceable solutions and found the (advertised) 4.00 solution was 4.15. I think it's a pretty big deal. If I hadn't noticed my meter giving me weird calibration matches I might have ruined some expensive wines.