Quick answer: Choose SDIC 60% if your priority is freight efficiency, premium markets, and effervescent tablet manufacturing (you ship 7% fewer kilograms per unit of active chlorine). Choose SDIC 56% for general distribution, price-sensitive markets, and widely available standard grade. SDIC 60% costs roughly 8–12% more per kilogram but typically saves 3–5% on total landed cost per ton of active chlorine delivered.
Sodium Dichloroisocyanurate (SDIC) is supplied globally in two main grades: SDIC 56% (also called SDIC 56) and SDIC 60% (SDIC 60). For first-time buyers and even experienced distributors, the choice between them is not always straightforward. This guide breaks down the economics, applications, and supply chain realities of both grades.
Chemical and Physical Differences
| Property | SDIC 56% | SDIC 60% |
|---|---|---|
| Available Chlorine (min.) | 56% | 60% |
| Moisture Content (max.) | 3% | 1% |
| Appearance | White powder/granular | White powder/granular |
| pH (1% solution) | 6.0–7.0 | 6.0–7.0 |
| Solubility (25°C) | 25 g/100 ml water | 25 g/100 ml water |
| Bulk Density | 0.96 g/cm³ | 1.00 g/cm³ |
| Crystal Structure | Dihydrate (2 H₂O molecules) | Anhydrous (no water) |
The fundamental difference is crystallization water content. SDIC 56% is the dihydrate form (Na(NCO)₃Cl₂·2H₂O), while SDIC 60% is the anhydrous form (Na(NCO)₃Cl₂). The 60% version simply has no water built into its crystal structure, so each gram contains more pure active material.
Cost Economics: Total Landed Cost Comparison
Most distributors evaluate chemical cost in USD per ton of available chlorine, not per ton of raw product. Here is a typical 2026 calculation for a 20-ton bulk shipment from China to a major Asian port:
| Cost Element | SDIC 56% | SDIC 60% |
|---|---|---|
| FOB price per ton | USD 1,250 | USD 1,370 |
| Ocean freight (per ton) | USD 110 | USD 110 |
| Insurance & duties (avg.) | USD 85 | USD 92 |
| Landed cost per ton of product | USD 1,445 | USD 1,572 |
| Active chlorine per ton | 560 kg | 600 kg |
| Landed cost per ton of active chlorine | USD 2,580 | USD 2,620 |
In this example, SDIC 60% delivers nearly identical cost per active chlorine ton while shipping 6.7% less weight — meaning lower warehouse storage costs, fewer pallets, and reduced handling fees throughout the supply chain.
Application Fit Analysis
When SDIC 56% Wins
- Price-sensitive emerging markets: Africa, parts of South America, and rural Southeast Asia where buyers compare unit price not total cost
- Standard powder repackaging: Distributors who simply rebag into 1kg/5kg consumer packs
- Aquaculture pond treatment: Where moisture content matters less because of immediate dissolution
- Widely available: Almost every chlorinated isocyanurate factory produces 56%, ensuring abundant supply and competitive pricing
When SDIC 60% Wins
- Effervescent tablet manufacturing: Lower moisture is essential for stable effervescent reactions
- Premium private-label brands: Higher chlorine content commands a quality premium in retail markets
- Long-distance ocean freight: Cost savings on per-kg freight stack up across container loads
- Pharmaceutical-grade applications: Hospital and clinical buyers prefer the cleaner anhydrous form
Forms and Packaging Available
SDIC 56% Common Formats
- Powder: 25 kg fiber drum, 50 kg HDPE drum, 1000 kg jumbo bag
- Granular (8–30 mesh): 25 kg drum
- Effervescent tablets: 1g, 2.5g, 8g (limited)
SDIC 60% Common Formats
- Powder: 25 kg fiber drum, 50 kg HDPE drum
- Granular: 25 kg drum
- Effervescent tablets: 1g, 2.5g, 20g (the gold standard for emergency water purification)
- Custom OEM packaging available with private labels
FAQ
Can I mix SDIC 56% and 60% in the same dosing system?
Technically yes, but it complicates batch documentation and quality control. Most professional operators standardize on one grade for traceability.
Does SDIC 60% really give more chlorine per dose?
Yes, exactly 7.1% more per gram. To deliver the same active chlorine, you use 6.7% less SDIC 60% than SDIC 56%.
Which grade has longer shelf life?
Both have 24-month shelf life under proper storage, but SDIC 60%’s lower moisture content gives it slightly better long-term stability in tropical climates.
Is SDIC 60% always more expensive?
FOB price per kg is higher, but on a “per kg of active chlorine” basis, the gap closes. For long-distance shipping, total landed cost often favors SDIC 60%.
Sourcing Recommendations
Shilan Chemical manufactures both SDIC 56% and SDIC 60% under ISO 9001 and Veterinary GMP standards, with annual capacity of 8,000 tons of SDIC products. We provide free samples, BAT (Best Available Techniques) compliance documentation, and custom OEM packaging for distributors and brand owners. Request a side-by-side sample pack to test both grades in your application.