Calculate how much water to remove for your aquarium water change. Enter tank volume and nitrate levels to get precise water volumes and frequency recommendations.
Enter your tank volume and change percentage to calculate exactly how much water to remove. Enter current and target nitrate levels to see how many changes are needed to reach your goal.
A 25–30% weekly water change is generally recommended. If nitrates exceed 40 ppm, increase frequency. Always match the temperature of new water to your tank and use a dechlorinator.
Water changes do more than dilute nitrates. Gravel vacuuming during changes removes organic waste buildup. Avoid overly large or frequent changes, which can stress fish through water parameter fluctuations.
Typical recommendation is 25-50% weekly for planted tanks, 25-30% for fish-only tanks. Heavily stocked tanks need more frequent changes. Monitor water parameters to determine optimal frequency.
Nitrate is the end product of the nitrogen cycle. It's less toxic than ammonia/nitrite but accumulates over time. Target is <20 ppm for planted tanks, <40 ppm for fish-only. Water changes remove nitrate.
This calculator estimates water change volume needed to reduce nitrate. Actual results depend on fish load, plant uptake, and filtration. Test nitrate levels to verify effectiveness.
Use dechlorinated tap water or RO water. Let tap water sit 24 hours to release chlorine, or use dechlorinator. Match temperature to tank water to avoid shocking fish. Test for heavy metals if concerned.
Remove water with a siphon or pump. Vacuum substrate while draining. Add fresh water slowly to avoid disturbing plants/fish. Match temperature and pH. Perform weekly for best results.