So for a few months now certain acros we’re showing some stress. I went crazy trying to figure it out. Tested all morning and night, tested po4 which went a little higher then I like. I like to be about .03 to .08 I was at .18 So I figured that was my issue. Worked on lowering my po4 slowly and finally got it down to about .07. Corals still were not looking right. So every few days I would test the big 3. Usually I just test alk since I’m on a calcium reactor and mag and cal once every 2 weeks. Well checking the big 3 nothing was off, everything was stable. So I was getting bored and decided I wanted to try the trident. Hooked it up, calibrated it like 60 hours later and it was showing my alk about 6.56. I tested with salifert and salifert read 8.5. I contacted Apex and they sent me a ticket. For giggles I decided to check a fresh batch of saltwater. Red Sea reg is at about 8 alkalinity. Made the water and brought it up to 77 degrees and tested my alk. It read over 10. I was like that is very strange. I then called a friend who gave me new calibration fluid and again it read low. He also tested my water with his trident and it read low with him as well. I went out and bought a Hanna kit and that confirmed it. The salifert kits were WAY off. 3 or 4 months racking my brain not think a test kit I’ve used for 10 years were this far off almost causing a total tank crash. Now I’m not out of the woods yet. I have a few weeks to see the amount of damage that it caused. Right now I set up a doser to bring my alk back up slowly. Been 5 days and I’m at 7.8 on the trident and Hanna. Just putting the warning out there because I know A LOT of us use these kits. Thanks for reading