SpaGuard® Chlorinating Concentrate – Granular Spa Sanitizer (2 lb / 5 lb)

SpaGuard® Chlorinating Concentrate is a fast-dissolving granular sanitizer built around sodium dichloro-s-triazinetrione (dichlor) at 99% or higher concentration. Dichlor is popular for spas because it dissolves quickly at any pH and doesn't add cyanuric acid buildup as fast as some other chlorine sources, which matters in the smaller water volume of a spa.

For routine maintenance, use ¼ teaspoon per 100 gallons every 15–20 minutes to bring free chlorine into the 1–3 ppm range; for a full superchlorination treatment, use 1 teaspoon per 100 gallons. It's the primary sanitizer for chlorine-run spas, and it also works as an occasional shock treatment in bromine, ozone, or mineral-sanitized spas when extra oxidation is needed. Available in 2 lb (SKU 42614BIO) and 5 lb (SKU 42616BIO) sizes.

As a corrosive oxidizer, always add the granules to water — never water to the granules — and wear eye protection while handling it. Store it sealed, dry, and away from other pool or spa chemicals to avoid a dangerous reaction.

Dichlor is popular specifically for spas because it's a stabilized chlorine — it dissolves quickly across a wide pH range and holds its sanitizing strength better in the smaller water volume and higher temperatures typical of a hot tub, unlike unstabilized chlorine sources that break down fast in warm water. This is different from the calcium hypochlorite or trichlor commonly used in pools, which dissolve more slowly and are formulated for much larger water volumes; using pool-grade chlorine in a spa can throw off calcium hardness or cyanuric acid levels faster than dichlor will.