HYDROS – REDUCING AGENT FOR INDIGO / WOAD VATS
Chemical name: Sodium Dithionite (Thiox) | Grade: Textile | Use rate: ≤ 25 g per 10 L vat
Hydros—also known as sodium dithionite, thiox, or hydrosulfite sodium—is the fast, reliable oxygen remover used to bring indigo or woad vats into reduction. A quick sprinkle over the surface turns the liquor a yellow-green and readies it for dipping within about an hour. However, for best performance leave the vat for 2 days before dyeing.
Why choose our Hydros
• Consistent, high-purity powder for rapid vat activation
• Cost-effective alternative to spectralite (use a little more, save a lot)
• Fine, free-flowing granules supplied in a resealable pouch
Directions (10 L vat)
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Set vat at 40 °C with indigo/woad and alkali already dissolved.
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Sprinkle 25 g Hydros evenly over the surface. Always add Hydros to water—never water to Hydros.
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Cover and wait ± 60 min. Vat should shift to yellow-green with a metallic film.
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Stir gently, keeping air out, then begin dipping.
In a nutshell
• Function: Oxygen remover / vat reducer
• Other names: Sodium dithionite, thiourea dioxide, thiox, hydrosulfite sodium
• Compatibility: Indigo, woad, other vat dyes
• Typical dose: 2–5 g · L⁻¹ (max. 50g per 10 L)
• Packaging: Resealable moisture-proof pouch
• Safety: Wear gloves & mask; store cool & dry away from acids and oxidisers
Safety & storage
Keep sealed, cool and dry. Avoid inhalation of dust. Add powder to water—never the reverse—to prevent rapid exothermic reaction. Dispose of spent vats according to local regulations and keep away from children.
Need a full setup? Pair with our Natural Indigo Kit for a ready-to-dye bundle.
