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Mineral Chemistry
KH (Carbonate Hardness)
The buffering capacity of water against pH swings - measured as bicarbonate and carbonate ions. Higher KH = more stable pH.
Unit: dKH Code: KH
📖 Overview
KH is one of the most important yet underappreciated parameters. It doesnt directly affect fish - but it stabilizes pH. Low KH (under 2 dKH) leaves pH vulnerable to swings; sudden pH crashes can kill entire tanks overnight. In reef systems, KH (alkalinity) is critical for coral calcification.
📈 How to Raise
Baking soda (sodium bicarbonate). Crushed coral. Aragonite. Two-part alkalinity supplements (reef).
📉 How to Lower
Peat moss. RO water dilution. Muriatic acid (industrial - use with extreme care).