Quick answer: If you need fast disinfection (drinking water, aquaculture, food processing) → choose SDIC. If you need sustained chlorine release for 3-7 days (swimming pools, cooling towers, large water bodies) → choose TCCA. Read on for the full breakdown that our team uses to advise 200+ international buyers each year.
1. What Are SDIC and TCCA?
SDIC (Sodium Dichloroisocyanurate, CAS 2893-78-9) and TCCA (Trichloroisocyanuric Acid, CAS 87-90-1) are both chlorinated cyanurate compounds — meaning they release hypochlorous acid (HOCl) into water in a stabilized way, protected from UV degradation by the cyanuric acid backbone. That is why they outperform simple bleach (sodium hypochlorite) in outdoor and long-cycle applications.
2. Side-by-Side Comparison Table
| Parameter | SDIC | TCCA |
|---|---|---|
| Chemical Formula | C3Cl2N3NaO3 | C3Cl3N3O3 |
| Available Chlorine | 56%-60% | ≥90% |
| Molecular Weight | 220.0 g/mol | 232.4 g/mol |
| pH (1% solution) | 6.0-7.0 (neutral) | 2.7-3.5 (acidic) |
| Dissolution Rate | Fast (2-3 min at 25°C) | Slow (30-60 min for 200g tablet) |
| Release Duration | Immediate | Sustained 5-7 days |
| Shelf Life | 3 years | 2 years |
| Bulk Density | 0.9-1.0 g/ml | 0.8-0.95 g/ml |
| Solubility (water) | 25% at 25°C | 1.2% at 25°C |
| Typical Ex-Works Price | US$1.05-1.35/kg | US$1.35-1.75/kg |
| Cost per kg Active Chlorine | US$1.83-2.25 | US$1.50-1.94 |
Prices reflect 2026 Q3 China ex-works FCL rates. Contact us for updated quotations.
3. Which One Should You Buy?
Choose SDIC when:
- You need rapid disinfection (drinking water treatment, aquaculture, food processing lines)
- You prefer neutral pH to avoid corroding stainless equipment
- You dose manually and cannot wait for slow-release tablets
- You need NSF/ANSI 60-listed products for potable water
Choose TCCA when:
- You want long-cycle disinfection (5-7 days per tablet in swimming pools)
- You need the highest chlorine per kg (90% vs 60%) for shipping efficiency
- Your dosing is automatic (feeders, floating dispensers)
- You are OK with slightly acidic pH (which suits pool water balance)
4. FAQ from B2B Buyers
Q1: Can I use SDIC and TCCA interchangeably?
A: No. TCCA’s slow release means it under-dosages fast-consumption water. SDIC’s neutral pH means it over-shocks pools with delicate pH balance. Match the chemistry to the application.
Q2: Which one is cheaper for the same disinfection effect?
A: TCCA gives you ~25% more available chlorine per USD when calculated correctly (see table). But TCCA is only cheaper when you can use its slow-release characteristic — otherwise you waste chlorine.
Q3: How do I know I am getting real 90% TCCA and not 85% adulterated?
A: Request an SGS or Intertek pre-shipment inspection. Shilan provides third-party COA on every shipment, plus retention samples for 24 months.
5. Common Mistakes We See From New Buyers
- Buying TCCA tablets for drinking water — slow release + acidic pH = wrong tool
- Buying SDIC for outdoor pools without cyanuric acid backup — chlorine burns off in UV within hours
- Overpaying for “90% pure” SDIC — the 60% ceiling is a chemistry limit, not a quality one
- Storing in metal drums — corrodes containers and releases toxic chlorine gas; use HDPE only
- Mixing SDIC and TCCA in the same feeder — pH conflict, potential explosive reaction
Ready to Order?
Shilan Chemical produces both SDIC and TCCA at ISO 9001 / NSF-listed facility in Hebei, China. MOQ 1 metric ton, samples available, 12-hour quote turnaround. Request a quote →