Pool Chlorinators: Reviews and Ratings

Pool chlorinators are mechanical or chemical-feed devices that deliver a controlled, metered dose of chlorine to swimming pool water, replacing the manual practice of broadcasting granular or liquid chlorine directly into the pool. This page covers the principal chlorinator types — tablet feeders, erosion feeders, inline and offline models, and saltwater chlorine generators — along with how each works, where each applies, and the technical and regulatory factors that govern selection. Understanding chlorinator classification matters because equipment choice directly affects water chemistry stability, bather safety, and compliance with nationally recognized standards.

Definition and scope

A pool chlorinator is any device engineered to introduce chlorine sanitizer into pool water at a controlled rate, independent of manual application. The category encompasses three distinct equipment families:

1. Erosion feeders (offline and inline) — bypass-type cylinders that allow pool water to flow over or through trichlor or dichlor tablet pucks, dissolving them at a rate governed by a flow-control valve.
2. Automatic chemical feeders — peristaltic or diaphragm pump-based systems that inject liquid chlorine (sodium hypochlorite, typically 10–12% concentration) in precise doses timed to a controller signal.
3. Saltwater chlorine generators (SCGs) — electrolytic cells that split dissolved sodium chloride (NaCl) into chlorine gas and sodium hydroxide at the cell plates; the chlorine immediately dissolves into hypochlorous acid.

The National Sanitation Foundation (NSF) Standard 50, administered jointly with the American National Standards Institute (ANSI), establishes minimum performance and material-safety requirements for pool circulation and water-treatment equipment, including chemical feeders and electrolytic chlorine generators (NSF/ANSI 50). Equipment lacking NSF/ANSI 50 certification may not pass local health department inspections in states that adopt the Model Aquatic Health Code (MAHC) published by the Centers for Disease Control and Prevention (CDC MAHC).

Pool equipment certifications and standards provides a reference-grade breakdown of applicable standards across the full equipment spectrum.

How it works

Erosion feeder mechanism: Water enters a bypass line, passes through the feeder canister loaded with 3-inch trichlor tablets (90% available chlorine, acidic pH ~2.8–3.0), dissolves a controlled surface layer of tablet material, and returns downstream of the filter. Flow rate through the canister — adjusted by a needle valve — determines dissolution speed and, therefore, chlorine output. Trichlor adds cyanuric acid (CYA) as a stabilizer byproduct; CYA accumulates over the season and requires dilution once levels exceed 80–100 ppm, per MAHC guidance.

Liquid chemical feeder mechanism: A chemical metering pump draws from a sodium hypochlorite reservoir and injects a precise volume per stroke into the return line. Output is typically expressed in gallons per hour (GPH) or milliliters per stroke. Controller-integrated models accept an ORP (oxidation-reduction potential) or free-chlorine sensor signal to modulate output automatically, a configuration often specified for commercial pools under MAHC Section 5.

Saltwater chlorine generator mechanism: An SCG controller passes low-voltage DC current through a titanium cell coated with ruthenium or iridium oxide. Dissolved salt at a concentration of 2,700–3,400 ppm undergoes electrolysis, producing hypochlorous acid continuously while the pump runs. Output is measured in pounds of chlorine per 24-hour period; residential cells commonly range from 0.5 lb/day to 2.0 lb/day. A dedicated review of SCG equipment is available at saltwater chlorine generators reviews.

Because chlorinators introduce chemical reactions into the water stream, installation must follow the manufacturer's listed instructions and applicable local codes. The Uniform Plumbing Code (UPC), maintained by the International Association of Plumbing and Mechanical Officials (IAPMO), governs chemical injection point placement and backflow prevention requirements in many jurisdictions (IAPMO UPC).

Safety standards for chemical storage adjacent to chlorinator equipment fall under OSHA Hazard Communication Standard 29 CFR 1910.1200 for commercial operators, and the NFPA 400 Hazardous Materials Code for quantities exceeding threshold volumes (NFPA 400).

Common scenarios

Residential inground pools with low-maintenance priority: Inline or offline erosion feeders with trichlor tablets represent the lowest-cost entry point. A 5-lb canister loaded with 3-inch pucks can sustain a 20,000-gallon pool for approximately 7–10 days between refills at normal bather loads. The tradeoff is CYA accumulation and the need to monitor pH drift downward caused by trichlor's low pH.

Residential pools prioritizing reduced chemical handling: Saltwater chlorine generators eliminate weekly tablet purchases and reduce direct chemical contact. Salt cells carry an operational lifespan of 3–7 years depending on calcium hardness management and cleaning frequency, per manufacturer documentation from Pentair and Hayward — both of whom publish cell-life data in their NSF-listed product specifications. Compatibility questions across brand platforms are addressed in the pool equipment compatibility guide.

Commercial and public pools under health code inspection: Liquid chemical feeders with ORP controllers are the dominant specification in commercial facilities. The MAHC requires that public pool water maintain free chlorine levels between 1.0–10.0 ppm (depending on pool type and cyanuric acid level), with automated control systems strongly preferred. Peristaltic pump feeders allow precise log documentation of chemical consumption, which supports the operational records required during health inspections.

Supplemental sanitization systems: Chlorinators are increasingly paired with UV pool sanitizers or ozone pool sanitizers in a layered approach; in these configurations, the chlorinator's output rate is reduced because the secondary system addresses pathogen load, and chlorine is maintained primarily as a residual.

Decision boundaries

Selecting the appropriate chlorinator type depends on four discrete decision factors:

1. Pool classification (residential vs. commercial): Commercial pools in jurisdictions adopting the MAHC must meet automated chemical feed requirements; erosion feeders alone do not satisfy the monitoring and logging provisions of MAHC Section 5.7.
2. Water volume and bather load: SCGs sized undersized for pools above 40,000 gallons will produce insufficient residual; output in lb/day must be matched to pool volume, turnover rate, and expected chlorine demand.
3. CYA management tolerance: Erosion feeders using trichlor steadily raise CYA; pools in hot climates with high evaporation rates may need partial draining 1–2 times per season to reset CYA below 80 ppm. Liquid sodium hypochlorite feeders and SCGs add zero CYA.
4. Installation code compliance: Inline erosion feeders installed before the filter violate manufacturer guidance and most local codes, because concentrated chlorinated water contacts filter media at high concentration. Downstream installation — after the filter, before the heater — is the code-correct sequence per IAPMO and the pool equipment industry's installation standards summarized at pool equipment installation requirements.

An equipment cost and lifecycle comparison across chlorinator types is available at pool equipment cost analysis.

References

• NSF/ANSI Standard 50 — Pool and Spa Equipment
• CDC Model Aquatic Health Code (MAHC)
• IAPMO Uniform Plumbing Code
• NFPA 400: Hazardous Materials Code
• OSHA Hazard Communication Standard, 29 CFR 1910.1200