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Water Change Calculator

Calculate how much water to remove and replace

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Water Change Guidelines

✅ Recommended: 25-30% Weekly

Most aquariums thrive with 25-30% weekly water changes. This removes nitrates and replenishes minerals without shocking fish.

⚠️ Minimum: 10-15% Weekly

Lightly stocked, heavily planted tanks can manage with 10-15% weekly changes. Monitor nitrate levels.

💧 Large Changes: 40-50%

Use for emergency situations (high ammonia/nitrite), overstocked tanks, or breeding setups. Match temperature and pH closely.

Important Tips:

  • Always treat new water with dechlorinator
  • Match temperature within 2°C (4°F)
  • Vacuum substrate during water changes
  • Never change more than 50% unless emergency
  • More frequent small changes > occasional large changes

Maintenance Schedule

Weekly (25%)Every 7 days - Standard maintenance
Bi-Weekly (30%)Every 14 days - Light bioload
Twice Weekly (15%)High bioload or fry tanks

💡 Pro Tip: Download the Fishi app to set automatic reminders for water changes and track your maintenance history!