Alkalinity Too High: How to Lower It

There is no additive to lower alkalinity safely; you stop adding and let the tank consume it. Above 12 dKH with low nutrients, back off dosing today.

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Steps

• Stop or halve your alkalinity dosing. Coral growth consumes dKH daily; most tanks drift down 0.5-2 dKH per day once dosing pauses.
• Water changes with a lower-alkalinity salt mix speed the drop.
• Do not dose acid or vinegar to force it down; the pH swing does more harm than the high dKH.
• Retest daily; resume dosing at a lower daily amount once in range.