Understanding Alkalinity Consumption in Reef Tanks

Alkalinity (measured as dKH or meq/L) is arguably the most critical parameter for coral growth. It provides carbonate ions that corals use to build their calcium carbonate skeletons.\n\nTarget ranges:\n- Mixed reef: 7.5-8.5 dKH\n- SPS dominant: 7.0-8.0 dKH (stability matters more than exact number)\n- Fish-only: Less critical, 6-10 dKH acceptable\n\nConsumption factors:\n- SPS corals are the heaviest consumers\n- A mature SPS tank can consume 1-3 dKH per day\n- LPS consume much less\n- Coralline algae also consumes alkalinity\n\nSupplementation methods:\n1. Two-part dosing (calcium + alkalinity separately)\n2. Kalkwasser (calcium hydroxide in top-off water)\n3. Calcium reactor (dissolves aragonite media with CO2)\n4. All-in-one solutions (like Tropic Marin, Red Sea)\n\nGolden rule: Test daily and maintain consistency. A slow alkalinity decline is better than large swings from irregular dosing.