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Compatible Replacement for Waterway 817-3501. Cross-References Pleatco PRB35-IN, Unicel C-4335 and Filbur FC-2385.
SKU XLS-418 1PACK · UPC 810625020211
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Also fits: Pentair Rainbow Dynamic 35 →Sundance Tacoma 680 using 6000-136Other brands CMP 35 using 25393-000-000
The XLS-418 is a replacement cartridge for the Waterway 35 Sq. Ft. It replaces Waterway 817-3501, along with aftermarket Pleatco PRB35-IN, Unicel C-4335 and Filbur FC-2385.
Each cartridge is 4 15/16" in diameter and 9 1/4" long with a 2 1/8" open end cap top and bottom, and carries 35 sq ft of filter media.
We make every cartridge in Austin, Texas, and shipping is free.
Measure your old cartridge cap to cap, then across the widest pleat.
How to measure a cartridge →Measuring your old cartridge
A variance of ⅛" is normal. Anything larger usually means a different housing model — check the number printed on your old cartridge against the compatible parts list before ordering.
Match your filter housing below, click any part number to verify the fit, or paste your existing part number into the search box.
Filter housings and systems this cartridge fits
OEM and competitor cartridge part numbers this product replaces
The Perfect Fit Guarantee applies to the cross-references listed here. Brand names, models and part numbers identify compatibility only. If your housing is not listed, reach out to our team before ordering.
Can't find your part number? Look it up on the full pool filter cartridge cross-reference chart.
Still unsure after reading these? Send us the number stamped on your old cartridge and we will confirm the fit.
The Excel Filters XLS-418 replaces Waterway 817-3501. Aftermarket equivalents: Pleatco PRB35-IN, Unicel C-4335 and Filbur FC-2385.
4 15/16" diameter, 9 1/4" long, 35 sq ft of filter media. Both end caps: 2 1/8" Open End. Measure your old cartridge before ordering if you are unsure of the part number.
No. The XLS-418 is an independently manufactured replacement cartridge, made in the USA by Excel Filters and built to match the Waterway 817-3501 specification. Waterway is a trademark of its owner, used only to show compatibility.
Most pool and spa cartridges last 1–2 seasons with regular rinsing. Replace it when cleaning no longer restores flow, the pleats fray, or the end caps crack.
XLS-408 • 1-Pack
Low stockReplaces: Pentair R173434, Pleatco PRB50-IN, Unicel C-4950, Filbur FC-2390
*Perfect Fit Guarantee applies to the OEM and aftermarket cross-references listed on this page; brand names, models and part numbers identify compatibility only. We ship to the 48 contiguous United States only; free standard shipping applies to those orders with no order minimum, and expedited service is priced at checkout. Every cartridge carries a 6-month limited warranty against defects in materials and manufacturing, separate from our 30-day return policy.
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