My alkalinity is currently at 7.3 which is low as it usually sits around 8.5DKH. And My calcium is off the charts on the salifert test kit, so I then used the low-resolution version and it says 600ppm. I created a different thread 3 days as I thought it was just my alkalinity that was low (my alk was at 6.7DKH a couple of days ago). I was previously using an API test kit for calcium at it says 420ppm for calcium, but I decided to buy a salifert one just to double-check, and sure enough, my calcium was off the charts today. I have been adding sodium bicarbonate slowly to raise the alkalinity as guidance from my other thread, but I am now seeking guidance as to what I should do. My alkalinity is at 7.3DKH and my calcium is at 600ppm.