Product Overview

The Pentair 59023500 Grid Assembly is a genuine replacement complete D.E. grid assembly designed for the Pentair FNS Plus 36 sq. ft. D.E. filter. This pre-assembled internal grid cluster replaces the filter’s worn, torn, cracked, or damaged internal grid set to help restore proper filtration performance.

This assembly is designed as a drop-in replacement for compatible 36 sq. ft. vertical-grid D.E. filters and includes the main internal grid components needed to replace the complete element cluster. It is ideal when individual grids are damaged, the manifold is worn, or the full internal assembly needs to be replaced.

Ideal For

Pentair FNS Plus 36 sq. ft. D.E. filter repairs
Replacing worn or torn D.E. grids
Replacing a damaged internal grid cluster
Restoring filter efficiency and water clarity
Pool service technicians
Residential pool filter maintenance
D.E. filter rebuilds

Key Features

Genuine Pentair replacement grid assembly
Designed for FNS Plus 36 sq. ft. D.E. filters
Complete pre-assembled internal element cluster
Includes eight 18-inch grids
Includes top manifold, bottom manifold, and tie rods
Drop-in design helps simplify filter rebuilds
Restores proper D.E. filtration performance
Ideal replacement when multiple grids or manifolds are damaged

Benefits

The Pentair 59023500 complete grid assembly helps restore filtration performance by replacing the internal D.E. grid cluster inside a compatible FNS Plus 36 filter. Over time, D.E. grids can tear, crack, warp, or become clogged with scale and oils that no longer clean out properly. Replacing the complete assembly can improve water clarity, filter efficiency, and system performance.

Because this is a complete pre-assembled grid assembly, it helps save time compared to rebuilding the filter with individual grids and manifold parts separately. This makes it a practical choice for service technicians and pool owners who want a cleaner, more efficient repair.

Specifications

Customer-Facing Q&A

What does the Pentair 59023500 replace?
The Pentair 59023500 replaces the complete internal D.E. grid assembly on compatible FNS Plus 36 sq. ft. D.E. filters.

Does this include all the grids?
Yes. This assembly includes eight 18-inch grids, commonly configured as seven full grids and one partial grid.

Is this already assembled?
Yes. This is commonly sold as a pre-assembled complete grid assembly, making it easier to install compared to replacing each grid individually.

Which filter does this fit?
This part is designed for the Pentair FNS Plus 36 sq. ft. D.E. filter, commonly listed as model FNSP36. It may also fit select older Pentair, PacFab, Purex, and American Products FNS Plus 36 sq. ft. filters.

Does this include the tank or filter housing?
No. This is only the internal grid assembly. It does not include the filter tank, clamp, lid, valve, plumbing, or D.E. powder.

When should I replace the full grid assembly?
Replace the full assembly if multiple grids are torn, cracked, warped, heavily scaled, or if the manifold or tie rods are damaged.

Confirm Before Ordering

Confirm your filter model and square footage before ordering. This assembly is for the FNS Plus 36 sq. ft. D.E. filter and uses 18-inch grids. It is not for FNS Plus 24, 48, or 60 sq. ft. models. Always relieve system pressure, shut off equipment, and follow the filter manufacturer’s service instructions before opening any pressurized filter tank.