無料硝酸塩削減計算機 - 換水プランナー | 水槽計算機

硝酸塩を目標値まで下げるために必要な換水回数を計算。効率的な換水スケジュールを計画しましょう。

FAQ

How does a water change reduce nitrate?

Each water change dilutes nitrate by the percentage of water replaced. For example, a 50% water change reduces nitrate by 50%. The formula is: NO3_after = NO3_current × (1 − changePercent/100). Multiple changes compound the effect.

What nitrate level is safe for fish?

For most freshwater fish, keeping nitrate below 20–40 ppm is recommended. Sensitive species (discus, shrimp, planted tanks) prefer below 10–20 ppm. Reef tanks ideally stay below 5 ppm.

How often should I do water changes?

For most tanks, 25–30% weekly is standard. Heavily stocked tanks or those with high bioload may need 30–50% weekly. Planted tanks can often go bi-weekly if plants absorb nutrients efficiently.

Does a bigger water change lower nitrate faster?

Yes — a 50% change halves nitrate in one step, while a 25% change removes only a quarter. However, large changes can stress fish through sudden parameter shifts. Gradual changes are safer for sensitive species.

Why isn't my nitrate going down?

If nitrate stays high despite regular changes, check your tap water — it may already contain 20–40 ppm nitrate. Overfeeding, overstocking, and under-filtration also keep nitrate elevated. Consider adding live plants or a refugium.