Well, I finally got a WORKING TRIDENT! For months I went back and forth with Neptune about how the trident wasn’t testing anywhere NEAR where all 3 of my manual Alk tests reported. I would test with Hanna, salifert, and LaMotte. They would all read 8.5 (+/- 0.1) yet the trident would sometimes read as low as 7 depending on which of the many methods I tried to calibrate it. I tried calibrating with neptunes solution and it would always read .6-.8dhk lower, when I calibrated with fauna Marin solution or the results of my manual tests on my tank water the trident would always report 1.5 lower then the given (known) values during calibration. Finally they had enough of hearing from me and sent me a brand new one. I just got around to setting it up, waited the 48 hours, then did a calibration with my tank water and results from my manual tests. They numbers FINALLY STUCK and now it reads exactly as my manual tests do! I’m beyond thrilled for myself, but feel the pain of you guys that are still having problems. My original trident was purchased and shipped from BRS. This one came from Neptune directly. The only thing I changed during the set up was I mounted it about a foot lower. Not sure if that did anything. I’m still convinced there is a bad batch of them out there and that was why my first one had so many problems.