SCHEDULER

Water Change Plan

How much and how often to change water โ€” based on tank age and stocking load.

25
% weekly
โ‰ˆ 5 gal per week ยท 1ร— /week

Why water changes matter

Partial water changes remove nitrates, replenish minerals and keep pH stable. The science: weekly 25% changes outperform monthly 50% changes for fish health โ€” smaller, more frequent changes avoid shocking the biological filter.

Tank stateWeekly change
New tank, cycling20% (avoid disrupting cycle)
Established, normal load25%
Heavy stocking30-40%
Overstocked / sick fish50% + treatment