How to Clean a Pentair Pool Filter - Sand, Cartridge, and DE

Pentair Filter Lines - Which Do You Have?

Pentair produces three filter families across two technology types. Each is cleaned differently. Identifying your exact filter before beginning any maintenance is essential. If your filter is a Hayward rather than a Pentair, see how to clean a Hayward pool filter for model-specific steps.

Finding your model number: The model number is on the label plate attached to the tank body. If the label is worn, the Triton II has a distinctive ribbed tank profile; the Clean and Clear Plus has “Pentair” and “Clean and Clear” embossed on the lid; FNS Plus filters have the square footage printed on the tank label.

Pentair Triton II Sand Filter - Backwashing Steps

The Triton II is Pentair’s flagship sand filter. The TR60 (60 sq ft, roughly equivalent to a 22” tank) handles pools up to 30,000 gallons; the TR100 handles pools to 40,000 gallons; the TR140 handles 50,000+ gallon pools. All share the same backwash process.

When to backwash: When the pressure gauge reads 8-10 PSI above your clean baseline reading. If your filter ran at 10 PSI when the sand was fresh and now reads 19 PSI, it is time.

Backwash procedure:

1. Turn off the pump. This is critical before touching the multiport valve. Moving the valve under pressure tears the internal spider gasket - a $20-40 part that requires valve disassembly to replace.
2. Set the multiport valve to BACKWASH. The Pentair Triton II multiport valve has six positions: Filter, Backwash, Rinse, Recirculate, Waste, and Closed. Turn the handle firmly to BACKWASH.
3. Turn the pump on. Water now flows backward through the sand bed, fluidizing it and lifting debris upward.
4. Run until the sight glass clears. The sight glass is a small clear window on the multiport valve body. Initially the water will run brown, grey, or cloudy. Run until it runs completely clear - typically 2-3 minutes. If your pool has had an algae treatment recently, run the backwash an extra minute.
5. Turn the pump off.
6. Set the valve to RINSE. This cycle flushes any remaining debris out of the standpipe and reseats the sand bed so it does not channel immediately on restart.
7. Run the pump for 30 seconds.
8. Turn the pump off. Move the valve to FILTER.
9. Restart the pump. Note the new clean baseline pressure.

Sand Dollar SD series: The procedure is identical. The SD40, SD60, and SD100 use the same multiport valve positions. The SD series is Pentair’s more compact option for smaller pools and above-ground installations.

Annual sand filter maintenance:

• Inspect and lubricate the multiport valve O-ring with Teflon-based pool lubricant (not petroleum jelly, which degrades O-ring rubber)
• Inspect the spider gasket inside the multiport valve - a cracked or compressed gasket causes the valve to leak water between positions
• After 5-7 years, replace the sand media. Use #20 silica pool filter sand; check your filter’s label for the exact sand capacity
  • Triton II TR60: 300 lbs of sand; TR100: 450 lbs; TR140: 600 lbs
• Pool filter sand #20 silica on Amazon

Pentair Clean and Clear Plus Cartridge Filter - Cleaning Steps

The Clean and Clear Plus (CC100 and CC150) is Pentair’s primary residential cartridge filter. The CC100 holds 100 sq ft of filtration area using 4 x 25 sq ft cartridges; the CC150 holds 150 sq ft using 4 x 37.5 sq ft cartridges. The oversized 160301 model holds 520 sq ft using 4 large cartridges.

Cartridge filters cannot be backwashed. The Clean and Clear Plus does not have a multiport valve or a backwash port. It uses a single closure bolt on the top lid and a 2-way valve. Do not attempt to reverse water flow through the cartridge elements.

When to clean: When pressure gauge reads 8-10 PSI above your clean baseline.

Cleaning procedure:

1. Turn off the pump. Use the breaker or timer to prevent accidental restart while the filter is open.
2. Open the air relief valve. On the Clean and Clear Plus, the air relief valve is on the top of the lid - a small push-button or screw-type bleeder. Open it until the pressure gauge reads zero and air stops escaping. This typically takes 15-30 seconds.
3. Remove the lid. The Clean and Clear Plus uses a single large closure bolt on top of the lid (a large hex bolt in the center). Loosen it counterclockwise. The lid lifts off straight up. Note: the lid has a large O-ring seal in a groove - set the lid aside face-up to protect the O-ring.
4. Lift out the 4 cartridge elements. The elements are held on a central manifold pipe. Lift the entire manifold assembly out, then remove each of the 4 cartridges from the manifold. Keep track of orientation.
5. Rinse each cartridge. Use a garden hose with a straight nozzle. Work from the top of each cartridge to the bottom, rinsing between every pleat. Rotate the cartridge a quarter turn and repeat until all pleat channels have been flushed. Do not use a pressure washer - the high pressure destroys the polyester fabric.
6. Chemical soak (monthly or as needed). Mix enzyme-based cartridge cleaner per label directions in a large bin or clean trash can. Submerge all 4 cartridges and soak for a minimum of 8 hours (overnight is ideal). This removes body oils, sunscreen, and calcium that rinsing alone cannot touch.
   • Pentair pool cartridge cleaner on Amazon
7. Rinse thoroughly after soaking. No chemical residue should remain.
8. Inspect each cartridge. Check for: holes in the pleated fabric (visible when held to light), collapsed pleats, cracked or separated end caps, permanent discolouration. Any of these indicate the cartridge needs replacement.
9. Lubricate the lid O-ring. Apply a thin film of pool-grade Teflon lubricant to the O-ring before replacing the lid. This prevents cracking and ensures a proper seal.
10. Replace lid and tighten closure bolt. Reinstall the central closure bolt - firm, not torqued. Restart the pump, open air relief to purge trapped air, close when water flows steadily.

Replacement cartridges for Clean and Clear Plus: Pentair part number R173573 for CC100; R173574 for CC150. These are sold as sets of 4.

• Pentair Clean and Clear replacement cartridges on Amazon

Cartridge lifespan: With proper cleaning and annual chemical soaking, Clean and Clear Plus cartridges typically last 2-3 years. Signs of end-of-life include inability to return to baseline pressure after cleaning and visible fabric damage.

Pentair FNS Plus DE Filter - Cleaning Steps

The FNS Plus is Pentair’s primary DE filter line. It uses a set of flat fabric-covered grid panels arranged around a central manifold. Filtration fineness is 3-5 microns - finer than any other residential filter type.

Routine maintenance - backwash and recharge:

The FNS Plus is backwashed using the multiport valve, exactly like a sand filter. However, backwashing removes the DE powder with the debris, so you must recharge with fresh DE after every backwash.

Backwash and recharge procedure:

1. Turn off the pump. Set multiport to BACKWASH. Run pump 2-3 minutes until sight glass clears.
2. Turn pump off. Set to RINSE. Run 30 seconds.
3. Turn pump off. Set to FILTER. Restart pump.
4. Immediately add fresh DE powder through the pool skimmer.

DE charge amounts for FNS Plus:

• FNS Plus 36: 7.2 lbs (use 7.5 lbs)
• FNS Plus 48: 9.6 lbs (use 10 lbs)
• FNS Plus 60: 12 lbs
• FNS Plus 72: 14.4 lbs (use 14.5 lbs)

Add DE slowly through the skimmer with the pump running. Do not pour the full amount at once - meter it in over 2-3 minutes using a DE scoop or measuring cup.

• Pool DE powder on Amazon

Annual FNS Plus teardown (required once per season):

Backwashing keeps the filter operational between seasons but cannot remove all accumulated scale, oils, and debris from the grid fabric. A full teardown is required annually.

1. Turn off the pump. Backwash thoroughly to pre-clean as much as possible before opening.
2. Release pressure via the air relief valve. Open until gauge reads zero.
3. Remove the multiport valve. Disconnect the plumbing unions on the valve inlet and outlet (hand-tighten only when reassembling). Remove the valve mounting bolts and lift the valve off the tank.
4. Pull out the grid manifold. The FNS Plus grid manifold is a central assembly with individual flat grid panels attached on both sides. Lift the entire assembly straight up and out of the tank.
5. Remove individual grid panels. Each panel slides off the manifold spine. Remove all panels and set aside.
6. Inspect every grid panel for tears. Hold each panel up to bright light - tears appear as bright spots in the dark woven fabric. Any torn grid must be replaced before reassembly. DE powder bypasses a torn grid and returns to the pool as a visible white cloud.
7. Rinse all grids. Rinse both sides of each grid panel with a garden hose.
8. Soak in DE filter cleaner. Place all grid panels and the manifold assembly in a large container with DE filter cleaning solution diluted per label directions. Soak for 2-4 hours. This removes calcium deposits and the oil film that builds up over a season.
   • Pool DE filter cleaner on Amazon
9. Rinse thoroughly. No chemical residue should remain on any grid or manifold surface.
10. Reassemble. Reattach grids to manifold, lower manifold into tank, replace multiport valve with fresh O-ring lubricated with Teflon pool lubricant, reconnect plumbing unions.
11. Recharge with DE. Restart pump, purge air via air relief valve, then add the full DE charge through the skimmer.

Replacement FNS Plus grids: Pentair part numbers are grid-specific by filter size. FNS Plus 60 uses grids Pentair part EC65 (set of 8). Individual grid panels run $20-35 each.

• Pentair FNS Plus replacement grids on Amazon

Pentair Quad DE Filter - Simpler Grid Design

The Quad DE (available in 60, 80, and 100 sq ft versions) is a different internal architecture than the FNS Plus. Instead of multiple small narrow grid panels, the Quad DE uses 4 large flat quad-style grids - each grid is a large rectangle approximately the size of a standard pool filter cartridge.

Advantages of the Quad design:

• Fewer individual parts to handle during teardown
• Grids are larger and easier to inspect for tears
• Cleaning the 4 large grids is faster than cleaning 8 smaller FNS Plus panels

Quad DE backwash procedure: Identical to FNS Plus - multiport valve to BACKWASH, run until clear, RINSE, return to FILTER, recharge with DE.

Quad DE recharge amounts:

• Quad DE 60: 12 lbs
• Quad DE 80: 16 lbs
• Quad DE 100: 20 lbs

Annual Quad DE teardown: Same steps as FNS Plus, but with 4 large grids instead of 8 smaller panels. The 4 large grids soak in a standard large trash can or utility tub. Pentair sells replacement Quad DE grids by filter size.

• Pentair Quad DE replacement grids on Amazon

Pentair Filter Parts to Keep On Hand

Stocking these parts prevents extended downtime when routine wear occurs.

• Pentair pool filter parts on Amazon
• Pool O-ring Teflon lubricant on Amazon

Related Guides

• How to Backwash a Pool Filter - Complete Guide
• How to Backwash a Pentair Pool Filter
• How Much DE to Add to a Pool Filter
• How Often to Clean Your Pool Filter
• Pool Filter Pressure Too High