Compare inline and off-line tablet feeders using their actual installation diagrams. “Flow-through” and “bypass” are loose category names; they do not tell you where an exact model’s inlet and outlet must connect or how water reaches the tablets.
The Hayward examples have different connections
| Model | Installation identity | Purchase implication |
|---|---|---|
| Hayward CL2002S | Inline CL200-family feeder with 2-inch socket connections | Needs a compatible location in the return plumbing and service access |
| Hayward CL220 | Off-line feeder with separate inlet and outlet tubing | Needs the manual’s specific connection points, suitable pipe and protected accessible tubing |
The Hayward CL-series manual places the CL220 inlet connection after the pump and before the filter, and its outlet connection after the heater or filter as applicable. It is therefore misleading to describe this exact installation as two arbitrary points on the final return pipe. Use the full current diagram, including its warnings and equipment-protection requirements.
This description explains the buying distinction; it is not a drilling or installation procedure. A qualified installer must reconcile the feeder and connected equipment manuals with the actual system.
Inline does not mean all water washes through the tablet stack
An inline body’s position in the main pipe does not establish that the entire circulation flow passes through the chemical chamber in the same way. Internal passages and the feeder control determine water contact with tablets. Do not use the main pump’s rated flow as a tablet-contact flow measurement.
Likewise, an off-line feeder depends on the hydraulic conditions between its specified connection points. Moving a connection because another pipe is easier to reach can change operation and equipment exposure. An adjustment dial cannot compensate for an installation that does not match the manual.
Compare the installation evidence
For the inline option, ask for the exact connection model, proposed equipment order, required protection and lid-service space; the CL2002S installation-fit worksheet turns those questions into a pre-order checklist. For the off-line option, ask for the marked inlet and outlet points, pipe compatibility, tubing route and inspection access.
Hayward’s clamp guidance refers to fitting around the outside of nominal 1.5-inch or 2-inch pipe. Do not interpret those nominal pipe names as measured outside diameters. Have the installer identify the actual pipe standard and supplied fitting compatibility before ordering.
A crowded pad may favor an off-line layout, but only if its documented connections and service route work. An open return segment may favor inline, but only if equipment protection, flow conditions and clearance also fit. Neither category automatically wins on output accuracy or long-term reliability.
Maintenance costs differ in location
Both systems require the exact approved slow-dissolving trichlor product, safe storage, water testing and manual-directed servicing. The off-line arrangement adds exposed tubing and connections to inspect. The inline arrangement places its body and connections directly in the main return route.
Record replacement-part identities and the service procedure with the installed model. Do not remove residue, open a lid or alter valves using a generic sequence from a comparison article. Never mix products or put shock into a tablet feeder.
Choose from a complete quote
The affiliate offers on this page identify the CL2002S and a clearly labeled CL220 search. Confirm the exact suffix and supplied hardware before purchasing. Compare total installation and service requirements, not just the feeder price.
For other named models and published capacities, use the feeder fit map . If continued trichlor use does not fit the water’s stabilizer level, neither plumbing layout resolves that chemistry problem.
Research basis: Hayward’s CL-series manual and chemical-feeder specifications , with CDC chemical-safety guidance . The hydraulic explanation was checked September 23, 2026; no installed flow or output was measured.
Exact-model buying routes
View the Hayward CL2002S on Amazon or search Amazon for the Hayward CL220 off-line feeder . The CL220 link is a model search; confirm the actual listing and included hardware. Smart Pool Care may earn a commission from qualifying purchases.