A simple weekly rhythm
Many community tanks do well with about 20–30% weekly changes, adjusted for stocking and test results. Heavily stocked tanks may need more; lightly stocked planted tanks may need less.
Test occasionally so you are not guessing. Clear water is not the same as safe water.
Step-by-step
- Turn off heaters/filters if your routine needs it for safety, then siphon water while gently vacuuming debris from the substrate.
- Prepare replacement water: similar temperature, treated with dechlorinator suitable for your volume.
- Refill slowly. Restart equipment and check fish for stress.
- Do not scrub all filter media in tap water on the same day — you can crash your cycle.
Common mistakes
Changing 80% because the tank “looks dirty,” skipping dechlorinator, or cleaning every biological surface at once.
If ammonia or nitrite appears, pause stocking and troubleshoot before adding more fish from MateLoop or elsewhere.
Water chemistry varies by region and species. Use test kits and local advice for your setup.