ChloroKlean Plus L20 Dosing Guide
How to obtain and verify a product-specific Plus L20 dose. This guide gives no substitute dose, residual or contact time.
ChloroKlean Plus L20 is supplied for stated Great Britain PT2, PT4, PT5 and PT11 uses under applicable GB BPR transitional arrangements while the relevant precursor-route and product-type combinations remain in the GB Review Programme. It is not claimed to hold full GB, EU or Northern Ireland product authorisation. This page does not replace the product label, Technical Data Sheet or a site-specific written scheme.
How Dose Rate Is Calculated
The current product label and technical documentation must first support the intended use, organism and application method. A competent person then accounts for system volume, turnover, measured demand, water chemistry, contact time and representative monitoring points.
A residual at the dose point does not establish end-to-end treatment. Distal measurements, chlorite and chlorate where relevant, operational records and microbiological or surface validation must verify the programme.
Third-party chlorine dioxide studies and figures for another product or application are not Plus L20 dosing instructions.
Pools and Spas (PT2)
For pools and spas, use only the dose, contact time and application method supported by current PT2 product documentation and the competent site programme. HSG282 and applicable pool guidance govern monitoring and records.
Sample representative points to confirm circulation and control. Include chlorite and chlorate where specified, alongside pH, temperature, turbidity and microbiological quality.
Chlorine dioxide forms no chloramines and generally very little THM/HAA, but that does not guarantee no eye or respiratory irritation. Water balance, ventilation, bather pollution and individual sensitivity still matter.
Cooling Towers and Evaporative Condensers (PT11)
Assess Plus L20 for a PT11 cooling-system use only where the current label and technical documents support it. PT11 includes open and closed liquid-cooling and processing systems, but does not establish product suitability for every circuit. Assess system design, existing corrosion inhibitors, glycol, materials, operating conditions, dosing and monitoring.
For evaporative cooling systems, the current PT11 product conditions and the HSG274 Part 1 written scheme must set the dose, residual, monitoring frequency and acceptance criteria. In a closed-circuit evaporative cooler, assess the external spray-water circuit separately from the enclosed process-fluid loop.
No routine recommendation is made for inhibited closed heating or chilled-water loops without expressly supported current product instructions and written compatibility evidence. This is not a blanket ban on chlorine dioxide, nor a recommendation to use remedial or shock dosing in those loops.
Measure at representative points and trend residual, microbiology and operating conditions at the frequency in the written scheme.
Do not infer a higher-dose biofilm treatment from general studies. Any remedial concentration and contact time must be expressly supported by the product documentation and site plan, then verified.
Drinking Water and PT5 Applications
For PT5 uses, the current product conditions and competent water-safety plan must set the dose and target residual. Chlorine dioxide, chlorite and chlorate must be measured against the applicable water-supply requirements; compliance values are not dosing targets.
Monitor residual at multiple distal points and at the point of use. Where the system has any reach to retail or domestic supply, the operator must have a competent water treatment specialist and an agreed monitoring regime.
For backflow from secondary use into the wholesome supply, refer to the Water Supply (Water Fittings) Regulations and the relevant water company's risk fluid category guidance.
Food Contact Surfaces and CIP (PT4)
For food-contact surfaces, use only the working concentration, contact time, application method and rinse supported by the current PT4 product documentation for the organism, soil and surface.
For Clean-in-Place loops, product-specific evidence and validation against HACCP critical control points are required. A generic chlorine dioxide log reduction is not a Plus L20 instruction.
Operator PPE for handling concentrate at make-up dilution is mandatory in line with the Safety Data Sheet.
GB BPR status and verification
ChloroKlean products are supplied for their stated Great Britain uses under applicable GB BPR transitional arrangements while the relevant chlorine dioxide precursor-route and product-type combinations remain in the GB Review Programme. This is not a claim of full product authorisation. No EU or Northern Ireland authorisation is claimed.
Verify the exact precursor route and product type, current Review Programme status and deadlines, the applicable GB Article 95 supply chain, product label and other national requirements. Article 95 listing is a supply-chain requirement, not product authorisation, an efficacy assessment or an HSE endorsement.
Key Data & Statistics
No generic dose
Each application requires current product conditions and competent assessment
Verify
Residual, by-products and efficacy must be measured under site conditions
PT2/4/5/11
Stated product types supplied under applicable GB transitional arrangements
Site-specific
pH response does not establish a dose or efficacy outcome
Plus L20 Dose-Setting Inputs by Application
Inputs that must be resolved from current product documentation and a competent site plan; this is not a dose table.
| Feature | Application | Product evidence needed | Site inputs | Verification |
|---|---|---|---|---|
| Spa / pool (PT2) | Label use, organisms, concentration and contact time | Volume, bather load, circulation and demand | Representative residual, by-products and microbiology | |
| Cooling tower (PT11) | Label use, concentration and application method | Loop volume, turnover, demand and discharge | Written-scheme residual, trends and microbiology | |
| Potable water (PT5) | Label use and water-supply conditions | Demand, hydraulics and water-safety plan | Chlorine dioxide, chlorite, chlorate and microbiology | |
| Food contact surfaces (PT4) | Organism, soil, surface, concentration, contact time and rinse | Cleaning method and HACCP controls | Product-specific surface validation |
No concentration or contact time is implied. Obtain current product instructions for the intended use.
How to Set the Dose Rate for a New Application
A sequence for obtaining a permitted product-specific dose and verifying it in the system.
Confirm Application and Lawful GB Route
Match the intended use to the relevant product type. Verify the applicable Plus L20 precursor-route and PT Review Programme status, Article 95 supply chain, current transitional deadline and label. Pull the SDS and TDS.
Establish System Volume and Turnover
Calculate the system volume in litres and the recirculation rate or turnover in volumes per hour. For pools and spas this comes from the pool plant design. For cooling towers, from the recirculation pump rating and cycles of concentration.
Set the Product-Specific Target
Use only the current product conditions and competent site plan to set a dose, contact time, residual and acceptance criteria. Do not use a generic starting range.
Commission and Measure
Commission under the site plan. Measure at representative points and adjust only within permitted product conditions, documenting demand, by-products and verification results.
Document and Continue Monitoring
Record the dose rate, monitoring frequency and acceptance criteria in the written scheme. Continue monitoring and review trends at the frequency set by the competent site plan.
Expert Insights
About the Reviewer
Gavin Owen
Managing Director, ChloroKlean
Gavin Owen leads ChloroKlean's technical and commercial operations, bringing over 20 years of experience in industrial chemical distribution and water treatment. He oversees product development, regulatory compliance strategy, and the company's BPR compliance programme across PT2, PT4, PT5, and PT11 product types. Gavin works directly with water treatment professionals, facilities managers, and public health engineers across healthcare, leisure, food processing, and industrial sectors.
Related Products
BPR-compliant chlorine dioxide products available from ChloroKlean.
Frequently Asked Questions
Common questions about this topic, answered by our technical team.
Important Safety Information
- ChloroKlean Plus L20 concentrate is a hazardous oxidiser. PPE per the Safety Data Sheet is required for handling.
- Do not mix the concentrate with other chemicals outside the documented dosing programme.
- This page intentionally gives no generic dose figures. Use the current product instructions and written scheme for the specific system.
- In potable water, the DWI combined condition for ClO2, chlorite and chlorate (0.5 mg/L as chlorine dioxide in water entering public supply) and the WHO provisional guideline values for chlorite and chlorate (0.7 mg/L each) apply; WHO sets no value for ClO2 itself.
- Operators of systems within scope of ACOP L8 must maintain a written scheme of treatment, risk assessment, and competent person oversight.
This guide is technical guidance only. It does not replace the product Safety Data Sheet, Technical Data Sheet, COSHH assessment, or the written scheme of treatment for the system being dosed. ChloroKlean products rely on applicable GB BPR transitional arrangements for stated Great Britain uses; Article 95 is not product authorisation, and no EU or Northern Ireland authorisation is claimed.
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Contact Technical Support
Get dosing calculations and product selection support from ChloroKlean's technical team.
Sources & References
This article references guidance from the following authoritative sources:
- ACOP L8: Legionnaires' disease - Control of legionella bacteria in water systems
HSE - Health and Safety Executive
- HSG274 Part 1: The control of legionella bacteria in evaporative cooling systems
HSE - Health and Safety Executive
- HSG274 Part 2: The control of legionella bacteria in hot and cold water systems
HSE - Health and Safety Executive
- Guidelines for Drinking-water Quality - Chlorine Dioxide
WHO - World Health Organization
- Drinking Water Inspectorate guidance
UK Government - Drinking Water Inspectorate
- GB Review Programme for existing biocidal active substances
HSE - Health and Safety Executive
- GB Article 95: the basics
HSE - Health and Safety Executive
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