Aquarium water change tracker for cleaner, safer tanks
Water changes are simple, but forgetting them is where the wheels come off.
Use TanksConnected to log water changes and connect them with test results, stocking and ongoing tank health.
Common water change and nitrate questions
Use the calculator for quick water change estimates and nitrate dilution checks.
- How much water should I change in my fish tank?
- Water change calculator for aquariums
- Nitrate dilution calculator
- How much will a 50% water change lower nitrate?
- How do I lower nitrate in a fish tank?
- How many litres is a 30% water change?
This public preview gives you a quick feel for the feature. Create a free account to save your own tanks, add livestock, record test results, and keep your aquarium history together inside TanksConnected.
Water change and nitrate dilution calculator
Estimate how many litres to change, what that may do to nitrate, and roughly how much dechlorinator the replacement water needs.
Water change details
Use actual tank volume where possible, not just advertised tank size.
Example: if your conditioner says 5 ml treats 250 L, enter 0.02 ml per litre.
Estimated result
This is simple dilution maths. It does not replace testing.
Extra water change guidance, FAQs and related tools
Routine changes
Weekly or regular water changes keep nitrate and dissolved waste under control.
Heavy-stocked tanks
Large or messy fish often need bigger changes, stronger filtration and closer nitrate monitoring.
Trend spotting
A log helps show whether your current schedule is enough or needs adjusting.
Water changes are still king
Filters process waste, but water changes remove what builds up. Tracking them keeps the basic husbandry honest.
Frequently asked questions
Why should I track aquarium water changes?
Tracking aquarium water changes helps you see whether your maintenance routine is consistent and whether nitrate, water clarity or fish behaviour improves after changes.
How often should aquarium water changes be done?
Water change frequency depends on tank size, stocking, feeding, filtration and nitrate build-up. Many aquariums benefit from weekly changes, but heavily stocked tanks may need larger or more frequent changes.
Should I record the percentage of water changed?
Yes. Recording the approximate percentage changed gives better context than only recording the date, especially when comparing water changes with nitrate readings or fish health.
Can filters replace water changes?
No. Filters process waste, but they do not remove everything that builds up in aquarium water. Water changes remain one of the most reliable parts of long-term fish tank care.