Alkalinity

Definition

Alkalinity is the water's buffering capacity against pH change. In aquariums, alkalinity is dominated by carbonate + bicarbonate ions and is consumed by coral skeleton building.

Practical use

Reef target: 8-9 dKH (most stable) up to 11-12 dKH (faster growth). Test 2x weekly; daily swings >1 dKH cause RTN in SPS.

Browse the full glossary for more aquarium terms.