Jandy CL Series Cartridge Filter, Large Cartridge, 340 sq. ft, 127 GPM, 60,960 gallons | CL340

Upgrade or replace your pool filter with confidence with the Jandy CL Series CL340. With 340 square feet of filter area and a maximum flow of 127 GPM, it can handle an 8-hour turnover of about 60,960 gallons.

The Jandy CL Series is a large four-cartridge in-ground pool filter offered in 340, 460 and 580 sq ft sizes with a 25 in footprint and 50 psi rating. The CL version uses universal unions for easy installation. Below we explain how cartridge filtration works, how to size a filter to your pump and pool, and how to keep it clean.

Jandy CL Series CL340 Specifications

Key Features of the Jandy CL Series CL340

• 340 sq ft filter area using four cartridges (4 x 85 sq ft each)
• Max flow 127 GPM; 8-hour turnover 60,960 gal
• 50 psi max working pressure
• Compact 25 in diameter footprint
• Corrosion-resistant polymer tank
• Universal unions simplify installation

How Pool Filters Work: Cartridge vs Sand vs D.E.

Every pool filter has the same job: catch dirt, debris and fine particles from the water the pump sends through it. The difference is the filter media.

• Cartridge filters use pleated polyester cartridges. They filter to about 10 to 20 microns, run at low pressure, and are cleaned by removing and hosing off the cartridges, so there is no backwashing and less water waste.
• Sand filters push water down through a bed of filter sand. They filter to about 20 to 40 microns and are cleaned by backwashing, which reverses flow to flush debris out to waste. They are simple and durable.
• D.E. filters use grids coated with diatomaceous earth powder and deliver the finest filtration, down to about 3 to 5 microns. They are backwashed and recharged with fresh D.E.

This model is a cartridge filter.

How to Size a Pool Filter

A filter must handle the full flow of your pump and still turn over the pool's volume in the target time, usually 8 hours for residential pools. Start with the pump: the filter's maximum flow rating should be equal to or greater than the pump's actual flow. Then check turnover: required GPM = pool gallons / 480 for an 8-hour turnover.

Many pool professionals size filters with extra capacity, especially cartridge filters. More filter area means lower pressure, cleaner water and longer time between cleanings, and it works hand in hand with variable-speed pumps that run at lower flow for longer periods.

Good, Better, Best: Where the Jandy CL Series CL340 Fits

At HVAC365 we organize every category into a simple Good, Better, Best framework so you can compare options without wading through jargon. Within our cartridge filter lineup, this model sits in the Better tier: Enhanced comfort and smarter control.

The Better tier steps up efficiency and adds smarter control. It balances up-front cost with lower operating cost and more convenience, which is why property managers and owners who plan to keep their equipment for years often land here.

Not sure the Better tier is right for you? Compare it with the Good and Best options in the same category. Whatever tier you choose, the equipment is brand new and covered by the full manufacturer warranty, and our team is here to help you weigh features against budget.

Installation Tips

Install the filter on a level pad after the pump and before the heater and chlorinator. Leave room above and around it to remove the lid, cartridges or grids, and to read the pressure gauge. Use the correct pipe size, support the plumbing so it does not stress the filter ports, and follow the manufacturer's pressure rating. Professional installation by a pool contractor is recommended, especially for new pads or when changing filter type.

Maintenance and Cleaning

• Write down the pressure gauge reading when the filter is clean. When pressure rises about 8 to 10 psi above that, it is time to clean.
• Remove cartridges and rinse them top to bottom with a garden hose. Soak them in a cartridge cleaner periodically to remove oils and scale.
• Replace cartridges when the pleats tear, flatten or no longer clean up, often every 1 to 3 years depending on use.
• Inspect the lid O-ring and air relief valve, and lubricate O-rings with a silicone-based lubricant.
• Drain the filter before winter in freezing climates.

Filtration by Region

In the South and Southwest, pools run year-round and face heavy pollen, dust, leaves and algae pressure in warm water, so larger filters and regular cleaning keep water clear. In drought-prone areas such as California, Arizona and Texas, cartridge filters are popular because they do not require backwashing, saving water. In northern climates, filters work hardest at spring opening; choosing a filter with ample capacity makes that cleanup much easier.

What's Included and Compatibility

This listing is for the Jandy CL Series CL340. Valves, unions and media may be sold separately unless listed.

Ideal for:

• Residential in-ground pools up to about 60,960 gallons (8-hour turnover)
• Pool/spa combinations needing long cleaning cycles
• High-flow systems with variable-speed pumps

Built for Homeowners, Contractors and Property Managers

• Homeowners: use our sizing tools and the pool math on this page, then reach out with your pool size, location and existing equipment. We will help you confirm the right model before you order.
• Contractors and installers: order in two clicks, follow every shipment with live tracking, and reorder common parts from the HVAC365 Contractor Portal. We know the labor shortage is real, so we focus on getting the right part to the job the first time.
• Property managers: manage equipment for multiple properties from one dashboard and book a strategy call with our team to standardize models, plan replacements and control maintenance costs.

Frequently Asked Questions About the Jandy CL Series CL340

What size pool can the Jandy CL Series CL340 handle?

About 60,960 gallons with an 8-hour turnover at its 127 GPM maximum flow. Many owners choose extra capacity for longer cleaning intervals.

Which filter type is best?

D.E. filters trap the smallest particles, cartridge filters save water and are easy to clean, and sand filters are simple and durable. The best choice depends on your priorities and local water rules.

How often should I clean my filter?

When pressure rises about 8 to 10 psi above the clean reading. For many pools, that is every few weeks to a few months.

Will this filter work with a variable-speed pump?

Yes, as long as the pump's maximum flow does not exceed the filter's rating. Lower flow rates often improve filtration.

Can I replace a sand filter with a cartridge filter?

Yes, with plumbing changes. Cartridge filters do not use a backwash valve, so the plumbing at the pad will be different.