Automatic pool chlorinators feed chlorine or bromine tablets into circulating pool water, but the right choice depends on plumbing, tablet size, and how much hands-on adjustment you want. I rank the Pentair Rainbow 320 as the best overall for buyers seeking an established in-line feeder, while the Hayward CL200 is a strong pick for a familiar in-line setup and the MAYGO CL220 offers an off-line option when cutting into pool plumbing is undesirable. The main tradeoff is straightforward: in-line models connect to the return line, while off-line feeders add installation flexibility but require separate plumbing connections. Capacity, replacement-part fit, and chemical compatibility matter as much as the brand name. Read on for the full comparison and advice on choosing a feeder that suits your pool system.
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Key Takeaways
- Installation style is the first dividing line: the MAYGO CL220 and Hayward CL220EF are off-line options, while most of the lineup connects directly to the return plumbing.
- The Pentair Rainbow 320 stands out as the strongest all-around in-line choice for buyers who want a recognizable feeder design rather than a replacement-style unit.
- Several entries are compatibility-focused alternatives: the R171096 and Hayward CL2002S replacement feeder target particular existing setups, so buyers should verify dimensions and fittings before ordering.
- A 9 lb capacity appears across multiple models, but capacity alone does not predict refill frequency. Tablet size, pool demand, feeder adjustment, and circulation schedules all affect how quickly tablets are used.
- The lineup includes both broad-use feeders and narrower-fit choices: compact or spa-oriented options such as the Pentair Rainbow 300 may suit specific installations better than a general-purpose pool feeder.
| automatic pool chlorinator | Model | Brand | Capacity |
|---|---|---|---|
| XtremepowerUS Inline Automatic | 90157 | XtremepowerUS | 9 pounds |
| MAYGO CL220 Offline Automatic | CL220 | MAYGO | 9 lb |
| XtremepowerUS Off-Line Automat | 90156 | XtremepowerUS | 9 lb |
| Swimline Hydrotools 87501 Auto | 87501 | Swimline Hydrotools | 4.2 lbs |
| Pentair Rainbow 320 Automatic | R171096 | Pentair | — |
| Swimline Hydrotools 8750 In-Li | 8750 | Swimline Hydrotools | 9.0 lb |
| R171096 Automatic In-Line Pool | R171096 | — | — |
| Automatic In-Line Pool Chlorin | CL2002S | — | 9 lb |
| Hayward CL2002S In-Line Automa | CL2002S | Hayward | — |
| Hayward CL200 In-Line Automati | CL200 | Hayward | — |
| U.S. Pool Supply In-Line Autom | USP CF-478 | U.S. Pool Supply | — |
| Hayward CL200EF Automatic Chlo | CL200EF | Hayward | 9 lb |
| Hayward CL220EF Off-Line Chemi | CL220EF | Hayward | 9 lb |
| MAYGO Automatic Inline Pool Ch | — | MAYGO | — |
| Pentair Rainbow 300 Automatic | R171016 | Pentair | — |
More Details on Our Top Picks
XtremepowerUS Inline Automatic Pool Chlorinator for 3-Inch Tablets
I’d shortlist this inline XtremepowerUS for an above-ground pool or smaller in-ground setup with plumbing that can accommodate a return-line feeder. Its 9-pound capacity means fewer tablet refills than the Swimline Hydrotools 87501, which holds 4.2 pounds, while the adjustable dial lets owners change the feed rate as conditions shift. It accepts 3-inch chlorine or bromine tablets, giving it more chemical flexibility than a feeder limited to one type. The tradeoff is that inline installation requires a suitable place in the return plumbing, and the product is specifically positioned for smaller pools rather than larger systems. Tablets are not included, so buyers need to source compatible slow-dissolving tablets separately.
Pros:- 9-pound capacity reduces how often tablets need replenishing compared with the 4.2-pound Swimline Hydrotools 87501.
- Adjustable dial allows the feed rate to be changed.
- Accepts 3-inch chlorine or bromine tablets.
- Heavy-duty resin construction is designed for pool-system use.
Cons:- Tablets are sold separately.
- Designed for above-ground and small in-ground pools, limiting its fit for larger systems.
- Inline installation requires a compatible return-line location.
Best for: Owners of above-ground pools or small in-ground pools who want a return-line feeder with a larger tablet reserve than compact models.
Not ideal for: Owners of larger pools or anyone unable to add a feeder to the return line; its stated pool fit is limited and inline installation depends on plumbing layout.
- Brand:XtremepowerUS
- Model:90157
- Installation:Inline, in pool water return line
- Tablet size:3 inches
- Capacity:9 pounds
- Maximum pressure:50 PSI
- Control:Adjustable dial valve
- Compatible with:Hayward CL200
- Tablets included:No
Our verdict“Choose this XtremepowerUS model if you have a smaller pool, 3-inch tablets, and return plumbing suited to an inline feeder.”
MAYGO CL220 Offline Automatic Pool Chlorinator, 9 lb
The MAYGO CL220 is the clearest fit here for owners replacing a Hayward CL220 or seeking an offline feeder that connects apart from the main return pipe. Its stated treatment capacity of up to 41,000 gallons gives buyers a useful sizing reference, and the adjustable knob lets them regulate feed speed and frequency. Unlike the inline XtremepowerUS 90157, this design avoids placing the feeder directly in the return line, which may suit plumbing layouts where an inline body is inconvenient. The tradeoff is that an offline setup still needs compatible connection points and installation space; the listing does not specify included hoses or fittings. Tablets are required and are not stated as included, so check the kit contents before ordering.
Pros:- Designed as a Hayward CL220 replacement and compatible with CL220 accessories.
- Offline installation keeps the feeder off the main return-line segment.
- Adjustable control knob regulates feed speed and frequency.
- Rated for water treatment capacity up to 41,000 gallons.
Cons:- Chlorine tablets are required and are not stated as included.
- Included installation hardware is not specified.
- Pool suitability is described for above-ground and indoor pools, not broadly for all pool types.
Best for: Pool owners replacing a Hayward CL220 or choosing an offline feeder for an above-ground or indoor pool within the stated 41,000-gallon capacity.
Not ideal for: Owners who need a complete installation kit with confirmed hoses and fittings, or who prefer a simple inline replacement like the XtremepowerUS 90157.
- Brand:MAYGO
- Model:CL220
- Installation type:Offline
- Capacity:9 lb
- Water treatment capacity:Up to 41,000 gallons
- Material:ABS
- Compatibility:Hayward CL220 replacement and accessories
- Pool types:Above-ground and indoor pools
Our verdict“Pick the MAYGO CL220 if you need an offline CL220-style replacement and your pool falls within its stated capacity.”
XtremepowerUS Off-Line Automatic Pool Chlorinator Feeder, 9 lb Capacity
This XtremepowerUS feeder pairs an offline layout with a 9-pound tank, making it a practical choice when owners want to keep the feeder out of the main return line without giving up a substantial tablet reserve. Its dial adjusts the feed rate, and it accepts slow-dissolving 3-inch chlorine or bromine tablets. Compared with the MAYGO CL220, it explicitly lists compatibility with both chlorine and bromine and gives a maximum pressure of 50 PSI; the MAYGO instead provides a stated treatment capacity of up to 41,000 gallons. This model’s fit is narrower: it is intended for above-ground and small in-ground pools, and its advertised 32 lb/hr maximum output does not replace proper pool sizing or water monitoring. Tablets are sold separately.
Pros:- Offline installation avoids placing the feeder directly in the return line.
- 9-pound capacity reduces refill frequency.
- Works with slow-dissolving 3-inch chlorine or bromine tablets.
- Dial control adjusts feed rate.
Cons:- Tablets are sold separately.
- Pool compatibility is limited to above-ground and small in-ground pools.
- No treatment capacity in gallons is provided.
Best for: Owners of above-ground or small in-ground pools who want an offline feeder for 3-inch chlorine or bromine tablets.
Not ideal for: Owners of larger pools or buyers who need a stated gallon-capacity rating; the MAYGO CL220 provides a specific treatment-capacity figure.
- Brand:XtremepowerUS
- Model:90156
- Type:Off-line automatic chlorinator
- Tablet compatibility:3-inch slow-dissolving chlorine or bromine tablets
- Capacity:9 lb
- Maximum pressure:50 PSI
- Maximum output:32 lbs/hr
- Material:Heavy-duty resin
- Pool compatibility:Above-ground pools and small in-ground pools
Our verdict“Choose this XtremepowerUS model if a 9-pound offline feeder for a smaller pool matters more than a published gallon-capacity rating.”
Swimline Hydrotools 87501 Automatic In-Line Chlorine Feeder
The Swimline Hydrotools 87501 is the compact-capacity choice in this group: its 4.2-pound chamber is far smaller than the 9-pound XtremepowerUS inline feeder, but that can suit a pool owner who wants a less bulky feeder or expects to manage tablet loading more often. It connects with 2-inch inlet and outlet fittings and uses an adjustable output dial to regulate dispensing through the existing pump and filter system. Its reinforced thermoplastic construction is described as corrosion- and UV-resistant. The smaller chamber is the main compromise, and installation fit depends on the existing plumbing. It accepts large or small slow-dissolving tablets and can handle chlorine or bromine, but the two chemicals must not be mixed in the feeder.
Pros:- Compact 4.2-pound capacity may suit installations where a larger feeder is unnecessary.
- Adjustable output dial controls dispensing.
- Works with large or small slow-dissolving tablets.
- Reinforced thermoplastic is described as corrosion- and UV-resistant.
Cons:- Smaller capacity means more frequent tablet replenishment than 9-pound models.
- Compatibility depends on the pool’s existing plumbing setup.
- Chlorine and bromine must not be mixed.
Best for: Pool or spa owners who want a smaller inline feeder for an existing system with compatible 2-inch connections.
Not ideal for: Owners seeking fewer refill intervals or a large tablet reserve; the XtremepowerUS inline model holds 9 pounds compared with this feeder’s 4.2 pounds.
- Brand:Swimline Hydrotools
- Model:87501
- Installation:Inline through existing pump and filter system
- Capacity:4.2 lbs
- Inlet and outlet connections:2 inches
- Compatible chemicals:Chlorine or bromine; do not mix
- Tablet compatibility:Large or small slow-dissolving tablets
- Construction:Double-reinforced thermoplastic
Our verdict“Choose the Hydrotools 87501 for a compact inline setup with compatible 2-inch plumbing, but skip it if refill intervals are your priority.”
Pentair Rainbow 320 Automatic In-Line Chlorine/Bromine Feeder
The Pentair Rainbow 320 stands out for buyers who want the largest stated tablet reserve among these five options: it holds up to 11 large tablets or 98 small tablets. That capacity exceeds the 9-pound XtremepowerUS inline feeder by tablet count, though the two figures use different measures and should not be treated as a direct weight comparison. It installs in the return line with no special venting required, and included adapters support 1½-inch connections as well as 2-inch slip PVC fittings. This makes it more adaptable to common connection sizes than the Swimline Hydrotools 87501, which lists 2-inch connections. The tradeoff is that unions are not included, so some installations may need extra plumbing parts. It suits pools and spas using slow-dissolving trichlor or bromine tablets.
Pros:- Holds up to 11 large or 98 small tablets.
- No special venting is required for installation.
- Includes 2-inch slip PVC fittings with adapters for 1½-inch connections.
- Suitable for pools and spas using bromine or slow-dissolving trichlor tablets.
Cons:- Unions are not included.
- Return-line installation requires a compatible plumbing location.
- Tablet capacity is stated by count rather than weight, making direct capacity comparisons difficult.
Best for: Pool and spa owners who want a high tablet count, return-line installation, and adapters for 1½-inch connections.
Not ideal for: Buyers who want all connection hardware supplied; unions are not included, and the Swimline Hydrotools 87501 may be a better fit for a simpler 2-inch setup.
- Brand:Pentair
- Model:R171096
- Item weight:4.5 pounds
- Tablet capacity:11 large or 98 small tablets
- Compatible tablets:Bromine or slow-dissolving trichlor
- Connection:2-inch slip PVC fitting; adapters for 1½-inch
- Installation:In-line return line; no special venting required
- Warranty:1 year
Our verdict“Choose the Rainbow 320 if you want a high tablet count and adaptable return-line fittings, and can supply unions separately.”
Swimline Hydrotools 8750 In-Line Automatic Chlorine Feeder
The Hydrotools 8750 is a practical choice for pool owners replacing a compatible in-line feeder without switching to an off-line setup. It ties into the existing pump and filter plumbing, then uses adjustable output to regulate chlorine delivery as water circulates. Its 9-pound capacity gives it a useful tablet reserve, while reinforced thermoplastic is intended to resist sun exposure and corrosion. Compared with the Hayward CL2002S, the Hydrotools is presented as a replacement for compatible major-brand feeders, but the Hayward listing specifies its tablet and stick compatibility more clearly. This feeder’s main tradeoff is installation: it must connect to pool plumbing, so it is not a portable or no-plumbing solution. I would shortlist it for owners matching its fittings to an existing in-line system.
Pros:- Feeds chlorine automatically through the existing pool circulation system
- Adjustable output gives owners control over chlorine delivery
- Reinforced thermoplastic is designed to resist UV exposure and corrosion
- Intended as a replacement for compatible major-brand feeders
Cons:- Requires connection to pool plumbing
- Specific pipe fittings and tablet dimensions are not stated in the supplied product details
Best for: Above-ground or in-ground pool owners replacing a compatible in-line feeder who want adjustable chlorine output and a 9-pound capacity.
Not ideal for: Pool owners who cannot modify or connect to their pump plumbing, or who need a feeder with specifically stated tablet dimensions and connection details.
- Brand:Swimline Hydrotools
- Model:8750
- Feeder type:In-line automatic chlorine feeder
- Capacity:9.0 lb
- Output:Adjustable
- Material:Double-reinforced thermoplastic
- Pool compatibility:Above-ground and in-ground pools
- System compatibility:Existing pump and filter systems
Our verdict“Choose the Hydrotools 8750 if you need an adjustable, 9-pound in-line replacement and can confirm it matches your plumbing.”
R171096 Automatic In-Line Pool Chlorinator, Compatible with Pentair Rainbow 320
This feeder is the most targeted option in this group: it is designed to replace Pentair R171096 and Rainbow 320 units, rather than serve as a universal in-line choice. Its stated range of 6,500–70,000 gallons helps buyers judge whether the system matches their pool, and capacity for up to 11 large or 98 small tablets can reduce how often it needs refilling. Adjustable flow control lets owners tune feed rate, while included 2-inch slip fittings and 1.5-inch adapters support compatible installations. Against the broader-fit Swimline Hydrotools 8750, this model offers more explicit replacement and fitting details, but its compatibility is narrower. The ABS construction and specified 12-month warranty are useful details; buyers outside the named feeder and plumbing fit should skip it.
Pros:- Designed as a replacement for Pentair R171096 and Rainbow 320 feeders
- Holds up to 11 large or 98 small tablets
- Adjustable flow control supports feed-rate adjustment
- Includes 2-inch PVC slip fittings and 1.5-inch adapters
Cons:- Compatibility is limited to the specified feeder models and suitable plumbing
- ABS construction is specified, but no UV- or corrosion-resistance claim is provided
- The 12-month warranty is a limited stated coverage period
Best for: Owners replacing a Pentair R171096 or Rainbow 320 who want stated tablet capacity, flow adjustment, and included compatible fittings.
Not ideal for: Pool owners with a different feeder design or plumbing that does not match the listed 2-inch slip fittings or 1.5-inch adapters.
- Model:R171096
- Compatibility:Pentair R171096 and Rainbow 320
- Material:ABS plastic
- Tablet capacity:Up to 11 large or 98 small tablets
- Pool size range:6,500–70,000 gallons
- Flow control:Adjustable
- Fittings:2-inch PVC slip fittings and 1.5-inch adapters
- Warranty:12 months
Our verdict“Pick this model when replacing a Rainbow 320 or R171096 and its adapters match your pool plumbing.”
Automatic In-Line Pool Chlorinator Replacement for Hayward CL2002S, 2-Inch PVC, 9 lb Capacity
This CL2002S replacement stands out for its clearly defined OFF-to-FULL dosage dial, including settings from 1 through 7. That range gives pool owners a direct way to change feed intensity, and its 9-pound capacity suits routine tablet-based maintenance. It connects to 2-inch PVC and is specified for slow-dissolving trichlor or bromine tablets, with a recommended flow rate of 50–90 GPM. Compared with the Hayward CL2002S, this option spells out its dial positions and lists a 36-month warranty, while the Hayward-branded model specifies a Viton seal and Easy-Lok cover. The tradeoff is a permanent PVC-glue installation, plus a strict opening procedure: the pump must be off and the dial set to OFF. It cannot take fast-dissolving chlorine tablets.
Pros:- OFF-to-FULL dial with settings from 1 through 7 allows dosage adjustment
- 9-pound capacity supports a substantial tablet load
- Designed for 2-inch PVC pool piping
- Specified for slow-dissolving trichlor or bromine tablets
Cons:- Requires permanent PVC-glue installation
- Cannot be used with fast-dissolving chlorine tablets
- Pump must be off and the dial set to OFF before opening
Best for: Pool and spa owners replacing a Hayward CL2002S who want a defined dosage dial and have 2-inch PVC plumbing.
Not ideal for: Owners who need a removable or portable feeder, use fast-dissolving chlorine tablets, or cannot make a permanent glued connection.
- Manufacturer:FOREBEN
- Model:CL2002S
- Compatibility:Hayward CL2002S replacement
- Installation:In-line; 2-inch slip connection bonded to PVC piping
- Capacity:9 lb
- Dosage control:OFF, 1–7, FULL
- Recommended flow rate:50–90 GPM
- Compatible tablets:Slow-dissolving trichlor or bromine tablets
- Warranty:36 months
Our verdict“Choose this replacement if you want a detailed dosage dial and can accommodate permanent 2-inch PVC installation.”
Hayward CL2002S In-Line Automatic Chlorine Chemical Feeder
The Hayward CL2002S suits pool owners who want an established in-line format that can dispense trichlor or bromine tablets or sticks. Its adjustable feed control works with a 50–90 GPM flow range, while 2-inch inlet and outlet ports define the plumbing it needs. The Easy-Lok cover provides access for loading, and the ABS body with a Viton seal gives buyers concrete material details. Compared with the generic CL2002S replacement in this lineup, this Hayward model lists tablet-and-stick compatibility and its seal material, while the replacement specifies a 9-pound capacity and a more detailed dosage scale. This feeder is less suitable if your plumbing does not match its ports or your system falls outside the stated flow range. It also relies on slow-dissolving chemicals and a working pump-and-filter system.
Pros:- Accepts trichlor or bromine tablets or sticks
- Adjustable feed control supports chlorine delivery changes
- Easy-Lok cover provides access for loading
- ABS body and Viton seal materials are specified
Cons:- Requires a compatible pump and filter system
- Requires 2-inch inlet and outlet connections
- Designed for slow-dissolving tablets or sticks
Best for: Pool or spa owners with compatible 2-inch plumbing who want to use slow-dissolving trichlor or bromine tablets or sticks.
Not ideal for: Owners without a compatible pump and filter system, with plumbing that does not fit 2-inch ports, or who need to use fast-dissolving chemicals.
- Brand:Hayward
- Model:CL2002S
- Feeder type:In-line automatic chemical feeder
- Compatible chemicals:Trichlor or bromine tablets or sticks
- Port size:2-inch inlet and outlet
- Flow rate:50–90 GPM
- Body material:ABS
- Seal material:Viton
- Use:Pools and spas
Our verdict“Choose the Hayward CL2002S if its 2-inch ports fit your system and you value stated bromine and stick compatibility.”
Hayward CL200 In-Line Automatic Chlorine Feeder for Pools
The Hayward CL200 keeps the setup straightforward: it uses the pool or spa’s existing circulation system to feed slow-dissolving trichlor or bromine tablets, with adjustable feed rate for routine control. Its threaded cover and finger-release catch give owners access without adding a more elaborate loading mechanism. Compared with the CL2002S, the CL200 listing emphasizes acceptance of large or small tablets and gives an item weight of 4 ounces, while the CL2002S specifies 2-inch ports, flow range, and compatibility with sticks. Those distinctions make the CL200 a better fit when tablet size flexibility matters more than the extra connection details provided for its counterpart. The tradeoff is shared with other in-line feeders: it depends on compatible pump-and-filter plumbing and is not intended for fast-dissolving chlorine. Its stated pool fit covers in-ground and above-ground pools.
Pros:- Automatically feeds chemicals through a compatible pump and filter system
- Accepts large or small slow-dissolving tablets
- Adjustable feed rate allows delivery changes
- Threaded cover and finger-release catch support access and closure
Cons:- Requires a compatible pool or spa pump and filter system
- Designed for slow-dissolving tablets rather than fast-dissolving chlorine
- Port size and flow-rate details are not supplied in the product data
Best for: In-ground or above-ground pool owners seeking an in-line feeder that accepts large or small slow-dissolving tablets and has adjustable feed rate.
Not ideal for: Owners who need an off-line installation, require specified 2-inch connection details, or use fast-dissolving chlorine tablets.
- Brand:Hayward
- Model:CL200
- Feeder type:In-line automatic chemical feeder
- Compatible tablets:Slow-dissolving trichlor or bromine
- Feed rate:Adjustable
- Body material:ABS
- Seal material:Viton
- Item weight:4 ounces
- Pool compatibility:In-ground and above-ground pools
Our verdict“Pick the CL200 if you want adjustable, in-line tablet feeding and do not need the CL2002S’s stated port and flow specifications.”
U.S. Pool Supply In-Line Automatic Pool Chlorine Feeder, 9 lb
The clear locking cover gives this in-line feeder a practical advantage over the Hayward CL200EF: I can check the tablet supply without opening the unit. Its 9 lb capacity also suits owners who want fewer refill interruptions, while the adjustable feed control lets them moderate how quickly tablets dissolve. It accepts slow-dissolving trichlor or bromine tablets or sticks, offering more chemical flexibility than chlorine-only options. The tradeoff is that the product is specified as a Hayward CL200-compatible replacement, so buyers should confirm their plumbing and unit fit before ordering rather than assume it works in every in-line setup. Tablets are not included, and installation still requires integrating the feeder with pool plumbing. I’d choose it for refill visibility and broad tablet compatibility, not for a universal, plug-in installation.
Pros:- Clear cover makes remaining tablets or sticks easy to check
- 9 lb capacity can reduce refill frequency
- Adjustable feed-rate control
- Compatible with slow-dissolving trichlor or bromine tablets or sticks
Cons:- Compatibility is specified for Hayward CL200, so other plumbing setups need verification
- Tablets and sticks are not included
- In-line installation requires a suitable place in the pool circulation plumbing
Best for: Pool owners replacing a compatible Hayward CL200-style in-line feeder who want to see tablet levels and use either trichlor or bromine.
Not ideal for: Owners seeking an off-line feeder, a confirmed universal fit, or a package that includes treatment tablets.
- Brand:U.S. Pool Supply
- Model:USP CF-478
- Chemical capacity:9 lb (4 kg)
- Compatible chemicals:Slow-dissolving trichlor or bromine tablets or sticks
- Installation:In-line
- Compatibility:Hayward CL200 chlorinator
- Material:ABS plastic
- Included accessories:Installation accessories, instruction guide, and lid wrench
Our verdict“Choose this feeder if you have a compatible in-line setup and value visible chemical levels plus trichlor-or-bromine flexibility.”
Hayward CL200EF Automatic Chlorine Feeder for In-Ground Pools, 9 lb Capacity
The Hayward CL200EF is the clearest match here for an owner looking specifically for an off-line feeder for an in-ground residential pool. Its adjustable control dial gives the operator a way to tune tablet output, while the 9 lb capacity means less frequent loading than a smaller-capacity feeder. Unlike the in-line U.S. Pool Supply CF-478, this model is off-line, so the plumbing arrangement—not just the product name—should drive the choice. The supplied details do not spell out installation fittings or a compatibility list, which makes checking the existing circulation layout especially important. It also requires chlorine tablets, which are not included in the product details. I’d favor this Hayward when the pool type and off-line configuration are a match; the CL220EF may suit buyers who want its specified Easy-Lok cover and Viton seal details.
Pros:- Designed for in-ground residential pools
- 9 lb capacity reduces how often tablets need to be replenished
- Adjustable control dial regulates chlorine tablet output
- Off-line configuration provides an alternative to in-line models such as the U.S. Pool Supply CF-478
Cons:- Installation must match the pool’s plumbing configuration
- Chlorine tablets are not included in the provided product details
- The provided specifications do not list included fittings or detailed compatibility information
Best for: Owners of residential in-ground pools whose plumbing can accommodate an off-line feeder and who want adjustable chlorine tablet delivery.
Not ideal for: Above-ground pool owners or buyers who need detailed fitment and installation information before choosing a feeder.
- Brand:Hayward
- Model:CL200EF
- Capacity:9 lb
- Installation type:Off-line
- Pool type:In-ground
- Feed control:Adjustable control dial
- Product count:1
- UPC:610377003827
Our verdict“Pick the CL200EF if you have an in-ground pool with a compatible off-line plumbing layout and want a straightforward adjustable chlorine feeder.”
Hayward CL220EF Off-Line Chemical Feeder, 9 lb Capacity
Among the off-line choices, the Hayward CL220EF stands out for the maintenance details it specifies: an Easy-Lok threaded cover for tablet access and a Viton seal paired with an ABS housing. That makes it easier to judge its construction than the CL200EF, whose supplied details focus more on pool type and capacity. Both hold 9 lb and offer adjustable feed rates, so the deciding factor is less about refill volume and more about whether the CL220EF’s listed cover and seal suit your service preferences. It remains a manual-refill feeder, not an automatic chemical monitor, and the available information gives no installation or compatibility details. Compared with the MAYGO inline model, it avoids the specified PVC-glue installation, but only if your plumbing supports an off-line arrangement.
Pros:- 9 lb capacity can reduce refill frequency
- Adjustable feed rate supports changes in pool conditions
- Easy-Lok threaded cover provides access for refilling
- ABS housing and Viton seal are specified
Cons:- Requires manual refilling with chlorine tablets
- Installation and plumbing compatibility details are not provided
- Off-line configuration may not suit pools set up for an in-line feeder
Best for: Pool owners with a compatible off-line plumbing setup who want a large-capacity feeder with specified cover and seal materials.
Not ideal for: Buyers who need confirmed installation compatibility, an in-line feeder, or a system that does not require manual tablet refills.
- Brand:Hayward
- Model:CL220EF
- Feeder type:Off-line automatic chemical feeder
- Capacity:9 lb
- Feed rate:Adjustable
- Cover:Easy-Lok threaded
- Housing:ABS
- Seal:Viton
Our verdict“Choose the CL220EF if you need an off-line 9 lb feeder and value its specified Easy-Lok cover and Viton seal over the CL200EF’s pool-type focus.”
MAYGO Automatic Inline Pool Chlorinator – 9 lb, 1″ & 3″ Tablet Feeder
The MAYGO MG200 is the most explicitly sized option here for larger pools: its listed limit is up to 41,000 gallons, paired with a 9 lb tablet capacity and a control dial that runs from zero to full feed. That capacity claim gives buyers a useful selection point absent from the Hayward CL200EF and CL220EF details. It also accepts 1-inch and 3-inch tablets and fits standard 1.5-inch plumbing with adapters. The tradeoff is installation: this is an in-line unit installed with PVC primer and cement, not a simple plug-in replacement, and the product may need more pipe-routing space than an OEM unit. Its pressure-relief lid helps during refills, but it does not remove the need to plan the plumbing work. I’d pick it for stated pool-size coverage, not for the easiest retrofit.
Pros:- Specified for pools up to 41,000 gallons
- 9 lb capacity accepts 1-inch and 3-inch tablets
- Adjustable control dial ranges from zero to full feed
- Chemical-resistant ABS body and EPDM O-ring seal
Cons:- Installation requires PVC primer and cement, which are not included
- Longer body may require more installation space than an OEM unit
- Pipe routing may need adjustment rather than a direct replacement
Best for: Owners of pools up to 41,000 gallons who want an adjustable in-line feeder and are comfortable modifying PVC plumbing.
Not ideal for: Pool owners looking for a quick replacement without pipe changes or those unable to use PVC primer and cement during installation.
- Brand:MAYGO
- Model number:cl
- Tablet capacity:9 lb
- Maximum pool size:41,000 gallons
- Plumbing size:1.5-inch standard, with included adapters
- Material:Chemical-resistant ABS
- Seal type:EPDM O-ring
- Installation:In-line; PVC primer and cement required
Our verdict“Choose the MAYGO MG200 for its stated large-pool coverage and adjustable in-line feed if you can handle a more involved PVC installation.”
Pentair Rainbow 300 Automatic Pool and Spa Feeder
The Pentair Rainbow 300 earns a distinct place for buyers who want one off-line feeder for chlorine or bromine and may use it with a pool or spa. Unlike the MAYGO MG200, which is an in-line unit with a stated pool-size limit, the Rainbow 300 is presented as an enclosed off-line system and requires no special venting. Its NSF listing is another specified attribute for shoppers comparing feeder construction and documentation. The supplied product details do not state a capacity or adjustable feed control, so I would not choose it over the 9 lb Hayward CL220EF when refill interval and dosage adjustment are the main priorities. Also, unions are not included, which can add parts planning to installation. This is a better fit for chemical flexibility and off-line placement than for buyers seeking the clearest capacity or flow-control specifications.
Pros:- Compatible with chlorine or bromine
- Enclosed off-line design requires no special venting
- NSF listed
- Specified for pool and spa use
Cons:- Unions are not included
- Capacity and adjustable feed-rate details are not provided
- The listed dimensions may require planning for installation space
Best for: Pool or spa owners who want an enclosed off-line feeder that can dispense either chlorine or bromine and do not need a stated capacity figure.
Not ideal for: Buyers who prioritize a documented 9 lb capacity, adjustable feed-rate details, or included unions for installation.
- Brand:Pentair
- Model:R171016
- Feeder type:Automatic off-line
- Compatible chemicals:Chlorine or bromine
- Dimensions:14.75 x 22.25 x 23 inches
- Weight:3 pounds
- NSF listed:Yes
- Unions included:No
Our verdict“Choose the Rainbow 300 if pool-and-spa chemical flexibility and an enclosed off-line design matter more than a stated capacity or feed-control specification.”
How We Picked
I compared these 15 automatic pool chlorinators by the factors that most affect ownership: in-line versus off-line installation, stated capacity, tablet compatibility, likely fit with common plumbing arrangements, and the clarity of the product’s intended use. I gave greater weight to products with a clearly defined role and recognizable system compatibility than to listings whose names provide little detail. Capacity was treated as a practical convenience, not a measure of chlorine output or a guarantee of fewer refills.
The ranking favors versatility and decision clarity first, then separates specialty options by their best-fit use. The Pentair Rainbow 320 leads as a general in-line recommendation; Hayward’s CL200 and CL2002S models are stronger candidates for buyers matching a Hayward-style installation or replacement need. Off-line feeders rank well for plumbing constraints, while replacement units and less-documented models sit lower because buyers must verify fit more carefully. I also account for tradeoffs: an in-line feeder can require plumbing work, and an off-line design adds hoses and connections to maintain.
| automatic pool chlorinator | Brand |
|---|---|
| XtremepowerUS Inline Automatic | XtremepowerUS |
| MAYGO CL220 Offline Automatic | MAYGO |
| XtremepowerUS Off-Line Automat | XtremepowerUS |
| Swimline Hydrotools 87501 Auto | Swimline Hydrotools |
| Pentair Rainbow 320 Automatic | Pentair |
| Swimline Hydrotools 8750 In-Li | Swimline Hydrotools |
| R171096 Automatic In-Line Pool | — |
| Automatic In-Line Pool Chlorin | — |
| Hayward CL2002S In-Line Automa | Hayward |
| Hayward CL200 In-Line Automati | Hayward |
| U.S. Pool Supply In-Line Autom | U.S. Pool Supply |
| Hayward CL200EF Automatic Chlo | Hayward |
| Hayward CL220EF Off-Line Chemi | Hayward |
| MAYGO Automatic Inline Pool Ch | MAYGO |
| Pentair Rainbow 300 Automatic | Pentair |
Factors to Consider When Choosing Automatic Pool Chlorinators
Before choosing among these feeders, I would start with the pool system rather than the product label. A chlorinator must suit the plumbing and chemical routine already in place; a large capacity or familiar brand cannot compensate for a mismatch. These checks can help avoid installation surprises and make the comparison more useful.
Match the installation style to your plumbing
An in-line feeder sits in the pool’s return plumbing, so adding one may require cutting pipe and fitting the unit into the correct section. That can create a neat, permanent installation, but it is less convenient if the existing layout is crowded or difficult to modify. An off-line feeder connects through separate tubing, offering more placement flexibility while adding extra connections that need inspection. Do not choose by the words “in-line” or “off-line” alone; check the installation diagram against your equipment pad and return-line layout. If you are replacing an existing feeder, matching its connection style can reduce the scope of the plumbing work. For a new installation, include space for opening and servicing the feeder, not just room for the body itself.
Confirm tablet type and chemical compatibility
Pool feeders are generally designed for particular tablet chemicals, and the product name may not spell out every compatibility detail. Check the manufacturer’s instructions for the permitted tablet type and size before loading a feeder. Never mix different chemicals or use a feeder for a chemical the manufacturer does not approve; residues can react and create hazardous conditions. A model described for chlorine and bromine should still be checked against its manual and the chemical label. Tablet dimensions matter too: a feeder that accepts 3-inch tablets may not suit a routine built around smaller tablets. Keeping the feeder dedicated to one approved chemical avoids confusion during refills and maintenance.
Treat capacity as storage, not dosing performance
A stated 9 lb capacity tells you how much chemical a feeder can hold under the listed conditions; it does not tell you how much chlorine the pool receives each day. Actual use changes with pool volume, water temperature, sunlight, swimmer load, tablet size, and circulation time. A larger chamber can reduce refill interruptions, but it may also hold more chemical than a small pool needs at once. Begin with the manufacturer’s guidance and test pool water regularly rather than assuming a feeder setting will maintain a fixed level. Avoid filling the chamber beyond its instructions just to stretch time between visits. Buyers who travel often should plan for water testing and pool care beyond feeder capacity alone.
Check replacement fit beyond the product name
Replacement listings often name a compatible model, but similar names do not guarantee an exact fit. Compare the existing unit’s connection locations, pipe size, lid arrangement, and available clearance with the replacement specifications and diagrams. If the old feeder is still installed, record measurements and take clear photos before removing it. Pay attention to whether fittings are included or whether the installation calls for parts from the original unit. A small mismatch can turn a simple swap into extra plumbing work. When compatibility details are unclear, confirm them with the manufacturer or seller before relying on a model number alone.
Plan for maintenance and safe handling
Any tablet feeder needs periodic attention: tablets must be replenished, the feed setting may need adjustment, and seals and fittings should be checked for leaks or wear. Ease of opening and access to replacement parts can matter more over time than a small difference in chamber size. Follow the unit manual when depressurizing or opening the feeder, and keep chemical handling separate from other pool products. Do not open a pressurized feeder or breathe vapors from its chamber. If routine upkeep is likely to be irregular, choose a location that is easy to inspect and make water testing part of the maintenance schedule. Automation meters chemical into circulation; it does not replace pool testing or safe storage.
Pay more for fit and serviceability, not capacity alone
A higher-spec or premium feeder makes sense when it solves a real installation problem, fits an existing system cleanly, or offers a more suitable service setup. It is harder to justify paying more just for a bigger stated capacity if the pool’s chemical demand is modest. For a straightforward replacement, exact compatibility and access to the right fittings may be more useful than added features. For a new build, compare the labor and parts needed for each installation style alongside the feeder itself. Buyers with a spa or compact setup should check whether a pool-focused feeder is oversized for their routine. The best value is the model that fits the system and can be maintained safely, not simply the one with the longest feature list.
Frequently Asked Questions
Should I choose an in-line or off-line pool chlorinator?
Choose an in-line model when your return plumbing can accommodate a feeder and you want it integrated into that line. An off-line unit can be easier to place when direct installation in the return pipe is impractical, but it adds tubing and connection points to inspect. The right choice depends on the equipment-pad layout, available clearance, and whether you are adding a feeder or replacing one. Check the installation instructions before buying, since the plumbing work can outweigh small differences between models. If you are unsure about cutting or rerouting pool pipe, ask a pool professional to review the setup.
Can I use any chlorine tablet in an automatic feeder?
No. Use only the tablet chemistry and size approved by the feeder manufacturer, and follow the chemical label as well. A product listing may mention chlorine or bromine without covering every tablet formulation or dimension. Never mix chemicals or put incompatible products in the same feeder, even after one type appears to be used up. Check the manual before the first refill and keep the feeder dedicated to its approved chemical. This prevents compatibility problems and reduces the risk of dangerous reactions.
Is a 9 lb feeder enough for my pool?
Capacity by itself cannot answer that question because tablet use depends on pool size, weather, circulation, water conditions, and how the feeder is adjusted. A 9 lb chamber may mean fewer refills for one pool but more stored chemical than another pool needs. Use the manufacturer’s instructions to set the feeder and test the water routinely to see whether the output suits your pool. Do not treat a full chamber as a set period of chlorine supply. If you need longer intervals between maintenance visits, plan for regular testing and backup care as well.
Will a replacement feeder fit if the product says it is compatible with my model?
Compatibility wording is a useful starting point, not a substitute for checking the actual connections and dimensions. Compare the replacement’s pipe size, fitting positions, body clearance, and lid access with the installed unit. Also confirm whether the listing includes the fittings you need or expects you to reuse existing parts. Model numbers can have similar variants, so verify the exact version on your feeder and consult the manufacturer’s fit information if anything differs. Checking before removal can prevent extra downtime and unplanned plumbing work.
Can an automatic chlorinator replace regular pool-water testing?
No. A feeder meters tablets into circulating water, but it cannot measure whether the pool’s sanitizer level is appropriate. Sunlight, temperature, swimmer use, and water balance all affect chlorine demand, so the same setting can produce different results at different times. Test the water on a regular schedule and adjust the feeder according to its instructions and your readings. Do not raise the feed setting solely because the tablets seem to be lasting a long time. Safe chemical handling and routine pool maintenance remain necessary with any automatic feeder.
Conclusion
For most buyers choosing among these automatic pool chlorinators, I would start with the Pentair Rainbow 320 as the best overall when an in-line installation fits the plumbing. The XtremepowerUS inline feeder is a value-oriented pick for buyers who want a direct in-line design for 3-inch tablets, while the Pentair Rainbow 300 is the premium choice for a buyer whose pool-and-spa setup matches its intended use. Beginners should favor a clearly specified model that matches their plumbing and tablet routine, such as the Hayward CL200, rather than a replacement listing with uncertain fit. For buyers who cannot readily cut into the return line, the MAYGO CL220 is the specific off-line option to compare with the Hayward CL220EF. Before ordering, verify tablet compatibility, pipe connections, and service access; those details decide whether a feeder will work well in your pool.
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