How it works
Regular water changes are the most important part of aquarium maintenance, as they dilute nitrates and replenish essential minerals. Simply input your tank's water volume (use our Tank Volume Calculator if you aren't sure) and the percentage you want to change. The calculator tells you the exact volume of water you need to siphon out and replace.
Example
Scenario: You have a 200 Liter aquarium and perform a weekly 25% water change.
- Total Volume: 200 Liters
- Change Percentage: 25%
- Calculation: 200 × 0.25 = 50 Liters
Verdict: You need to remove 50 Liters of old tank water and prepare 50 Liters of fresh, dechlorinated water to replace it.
FAQ
How much water should I change weekly?
A standard recommendation is 20% to 30% weekly for a normal community tank. Heavily stocked tanks or those with messy fish (like goldfish or cichlids) may require 50% weekly water changes.
Can I change 100% of the water?
Avoid changing 100% of the water unless it is an absolute emergency (like a severe chemical spill). Massive water changes can shock fish due to sudden shifts in temperature and water parameters.