Sodium hypochlorite (NaOCl) — often called liquid chlorine or simply “hypo” — is a workhorse oxidiser for disinfection and effluent treatment. It’s widely used in municipal and industrial water treatment, sanitation, and textile and paper bleaching. Specifying it well comes down to three things: concentration, freshness, and storage.
Choosing a concentration
Sodium hypochlorite is sold as a solution, and the available chlorine content is what matters. Common commercial strengths sit in the 10–12% range for water-treatment use. Higher strength means fewer litres to dose and transport, but also faster decay and more careful handling.
When you enquire, specify:
- Concentration (e.g. 10% or 12% available chlorine)
- Packaging (cans, carboys or bulk/tanker)
- Quantity and delivery frequency — hypochlorite is best bought to a schedule because it degrades over time
Strength decays — buy to a schedule
Unlike a stable salt, sodium hypochlorite loses available chlorine over time, and decay accelerates with heat, light and higher starting concentration. For consistent dosing, this has two implications:
- Don’t over-stock. Order quantities you’ll use within a reasonable window rather than holding large volumes for months.
- Account for decay in dosing. If material has been stored a while or warm, the effective strength may be lower than the label — verify before critical applications.
Storage and handling
Store hypochlorite in a cool, dark, well-ventilated area, in compatible (typically HDPE) containers, away from acids and metals. Never mix with acids — doing so releases toxic chlorine gas. Keep containers appropriately vented as gas can build up, and handle with gloves and eye protection. As always, review the SDS before use.
Dosing notes
Effective dosing depends on the water’s chlorine demand, contact time and target residual. For drinking-water disinfection, treaters work to a target free-chlorine residual; for effluent, the goal is usually disinfection or oxidation of specific contaminants. Because requirements vary widely, dosing should be set against your own water analysis.
The bottom line
For dependable disinfection, match concentration to your dosing system, buy to a schedule to manage decay, and store cool and away from acids. Tell us your application, volume and delivery cadence, and we’ll recommend a concentration and packaging — and quote it within 24 hours.
