CALCULATOR
Water Change Calculator
Nitrate only leaves a tank through water changes and plant uptake. This works out the schedule that holds it in range.
Inputs
Volume per change (L)
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updates as you type
Changes to reach target
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Equilibrium nitrate (ppm)
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Frequency advice
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Source water note
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Each change removes a fixed percentage of whatever is present, so nitrate approaches an equilibrium rather than falling to zero. The equilibrium depends only on the production rate and the change size.
A change larger than 50% risks swinging temperature, pH and hardness enough to harm livestock. Reach a target with several moderate changes rather than one large one.
If source water nitrate is already high, larger or more frequent changes will not help. Pre-treating the source water is the only route.
Note. This calculator is a simplified model built on conventional ranges. It is not a measurement of your tank, and no outcome for any plant or animal is guaranteed. Confirm every figure with a test kit before acting on it.