Eight weeks ago, I installed the Trident automatic tester to my 400g reef. It is made for the Apex controller. Four times a day, the machine whirrs to life and measures alkalinity, calcium and magnesium. I tend to check the numbers constantly, and know the results are usually less than six hours old. It's allowed me to be "lazy, yet informed" and I love it.
With the information it provides, I can decide if I want to adjust the calcium reactor's internal pH level higher or lower. When the pH in the reactor is higher, it melts less media and reduces the dKH of the effluent. Conversely if the pH is lower, the media melts faster and increases the dKH coming out of the reactor. For the typical reefkeeper, measuring alkalinity is performed a few times a week if you want to keep SPS corals. Armed with that knowledge, I can quickly make a tiny adjustment to dial in that exact level I desire. My calcium reactor also provides calcium so that's a 'whatever' number, because I don't ever add liquid calcium by itself. The Trident's Magnesium results help me decide if I need to increase or decrease the amount of Magnesium Pronto my dosing pump pushes in each day. I decided to dose a small amount each day just to observe the Trident's graph - I wanted to see the number trending upwards. And that's exactly what it did.
Today I went ahead and looked at the weekly averages of each of those three tests, and compiled the data below. My target goal for Alkalinity is 9.3 dKH, and I've nearly got my system tweaked to keep it right where I want it. Calcium and Magnesium are less important *to me* in comparison, but I included them while I had the graphs open in front of me. Magnesium seems to be higher than necessary, so I'll stop dosing that for a few weeks.
I'm going to be running the Calibration test solution through the Trident in a few weeks, and will also test that solution with my own test kits to see how close they are.