利用人数・頻度に基づくスパの換水サイクルと必要水量・起動ショック量を計算します。
Enter your spa volume, typical number of bathers per session, and how many times per week you use it. The calculator uses the standard drain-and-refill formula to determine when TDS buildup requires a water change.
The recommended interval is calculated as: volume ÷ (bathers × uses/week ÷ 7 × 3). More bathers and more frequent use means more frequent water changes. A minimum of every 7 days is recommended regardless of usage.
A partial 50% drain and refill at half the recommended interval is a good compromise — it cuts water usage in half while keeping TDS under control. Always add a startup shock dose after refilling to bring chlorine to 10 ppm.