Dosing, alkalinity, salinity, volume, and water changes - with safe, gradual plans.
A growing reef eats alkalinity, calcium and magnesium faster than water changes can replace them - skeleton is literally built from them. Once demand outruns your water changes you top the elements back up daily instead of letting them sag between them. Stability matters more than hitting any particular number.
Test first, enter what you measured and what you want, and pick the salt you're using. Correct slowly: the calculator caps alkalinity at 0.5 dKH, calcium at 20 ppm and magnesium at 100 ppm per day, and splits anything bigger across days. Dose alkalinity and calcium at different times or in different spots - together in one stream they precipitate out as chalk.
Use net water, not tank size.