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Water Change Calculator
Work out exactly how many litres to remove for a partial water change, plus the dechlorinator dose for the fresh water you add.
A 25% weekly change is a solid default for most tanks. Heavy-stocked or messy tanks do better with 30–50% weekly. Dechlorinator dose assumes the standard 1 mL per 40 L — check your bottle's label.
Change Volume
Water to Remove
25.0 L
25% of tank
US Gallons
6.60 gal
Dechlorinator Dose
0.63 mL
for the fresh water
UK Gallons
5.50 gal
Per Month
107 L
4.3 changes
Monthly Dechlorinator
2.7 mL
Match the temperature of the new water and dose dechlorinator before or during refill. Never rinse filter media in tap water.
Related Reading
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