My tank currently consumes 0.2 dkh per day and roughly 10 ppm Ca and 10 ppm Mg per week. I use Red Sea Coral Pro salt which has 11.5 dkh, 450 ppm Ca, and 1350 ppm Mg. Without a water change during a week the dkh would drop by 1.4 along with 10 ppm Ca and Mg. Is this fine if the water change is done? Or does that much fluctuation irritate corals? Ultimately I'm looking at auto dosing and this would decide if 2 channels is fine or if I should do 4. This is for a 25 gallon tank