Hot Tub Calculator
Calculate the right chemical doses to maintain your hot tub water.
Hot Tub Details
pH Levels
Ideal range: 7.2 - 7.6
Chlorine (ppm)
Ideal: 3-5 ppm
Alkalinity & Calcium
Hot Tub Volume
400
gallons (1514 liters)
pH Adjustment
pH Increaser (Sodium Carbonate)
Amount4.0 tbsp
Dichlor Granules
Amount (tsp)4.0 tsp
Amount (tbsp)1.3 tbsp
Alkalinity Increaser
Baking Soda8.0 tbsp
Calcium Hardness Increaser
Calcium Chloride10.0 tbsp
Maintenance Schedule
Weekly Shock1.60 oz
Daily chlorine2.0 tsp
Drain & Refill Every~67 days
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Editorial Note
MyCalcBuddy Editorial Team
This page is maintained as an educational calculator reference.
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Formula Source: Standard Mathematical References
by Various
🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.