Quick answer: For routine pool maintenance, dose 2 grams of TCCA 90% per cubic meter of water (or 3.3 grams of SDIC 60%) to maintain a free chlorine residual of 1–3 ppm. For shock treatment after heavy use, multiply by 5x. Always test water before dosing.
Calculating the correct dose of chlorine donor is the single most important skill for pool operators, hotel maintenance managers, and water-treatment distributors. This guide provides the exact formulas used by Shilan Chemical‘s technical team to advise customers across 50+ countries.
Why Dosage Calculation Matters
Under-dosing leads to bacterial growth, algae blooms, and cloudy water. Over-dosing wastes money, irritates swimmers’ skin and eyes, and violates health codes in most jurisdictions. Getting the dose right saves an average pool operator 30–40% on annual chemical costs while ensuring compliance.
The Core Dosage Formula
The fundamental equation for chlorine dosing is:
Chemical Dose (grams) = Pool Volume (m³) × Target Chlorine (ppm) ÷ Available Chlorine (%)
For example, a 50 m³ pool needing 2 ppm free chlorine using TCCA 90%:
50 × 2 ÷ 90 × 100 ÷ 1000 = 0.111 kg = 111 grams of TCCA
Step 1: Measure Your Pool Volume
For rectangular pools: Length × Width × Average Depth × 1000 = Liters (divide by 1000 for m³).
For circular pools: π × Radius² × Average Depth × 1000 = Liters.
Step 2: Choose Your Target Chlorine Level
- Daily maintenance: 1–3 ppm free chlorine
- Heavy bather load: 3–5 ppm
- Shock treatment (after rain, algae, contamination): 10 ppm
- Hot tubs / spas: 3–5 ppm (higher water temperature = faster chlorine consumption)
Ready-to-Use Dosing Table for SDIC 60% and TCCA 90%
| Pool Volume | SDIC 60% Daily Dose | TCCA 90% Daily Dose | Shock Treatment (TCCA) |
|---|---|---|---|
| 20 m³ (small residential) | 67 g | 44 g | 222 g |
| 50 m³ (medium residential) | 167 g | 111 g | 556 g |
| 100 m³ (large residential) | 333 g | 222 g | 1.11 kg |
| 500 m³ (commercial) | 1.67 kg | 1.11 kg | 5.56 kg |
| 1000 m³ (Olympic-class) | 3.33 kg | 2.22 kg | 11.1 kg |
SDIC vs TCCA: Which to Choose for Your Pool?
Both products work, but each fits a different operational style:
- Choose TCCA 90% if you have a tablet feeder or floating dispenser and want unattended slow release (perfect for outdoor pools, vacation rentals)
- Choose SDIC 60% if you do manual dosing daily and need fast, neutral-pH dissolution (perfect for indoor pools, public pools requiring quick adjustments)
For more detailed product specs, see our complete product catalog.
Common Dosing Mistakes to Avoid
Mistake 1: Ignoring Cyanuric Acid (CYA) Levels
When CYA exceeds 50 ppm, free chlorine becomes “locked” and ineffective even at high doses. Test CYA monthly and partially drain if it exceeds 80 ppm.
Mistake 2: Mixing SDIC and TCCA Directly
Never mix the dry products. Dose them at different times of the day, ideally with at least 4 hours apart, to prevent dangerous chlorine gas release.
Mistake 3: Dosing in Direct Sunlight Without CYA
Without stabilizer, up to 95% of free chlorine evaporates within 2 hours under summer sun. Use TCCA (which contains built-in CYA) for outdoor pools.
FAQ
How often should I add SDIC or TCCA?
SDIC: daily for manual dosing pools. TCCA: every 5–7 days using slow-release tablets in a dispenser.
What’s the difference between 56% and 60% SDIC?
SDIC 60% contains less filler and is cheaper to ship per unit of active chlorine. SDIC 56% is more widely available globally. For B2B bulk purchasing, 60% offers better freight economics.
Can I use TCCA in a salt-water pool?
Yes, but salt-chlorinator systems already produce chlorine via electrolysis. Use TCCA only for shock treatment or when the salt cell is undersized.
Need Bulk Pricing or Custom OEM?
Shilan Chemical supplies SDIC 56%/60% and TCCA 90% to distributors worldwide, with full SGS-tested COA documentation. Contact our technical team for a customized quote based on your market and packaging requirements.