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Home Pentair Fiberglass D.E. Filter, FNS Plus | 48 Square Feet | EC-180008
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Pentair Fiberglass D.E. Filter, FNS Plus | 48 Square Feet | EC-180008

Pentair Fiberglass D.E. Filter, FNS Plus | 48 Square Feet | EC-180008 Pentair Fiberglass D.E. Filter, FNS Plus | 48 Square Feet | EC-180008 Pentair Fiberglass D.E. Filter, FNS Plus | 48 Square Feet | EC-180008

Parts AvailableParts Available
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  • Requires the use of a backwash valve or adapters (listed under purchase options)
  • High FlowTM manual air relief valve and continuous internal air relief work together to maintain efficient filtration and prevent over-pressurization.
  • Easily accessible 2" drain for efficient cleanout.
  • Online part number EC-180008 is the direct replacement for part number 180008
Q & A
  • Pentair Backwash Valve for use with DE & Sand Filters | Push-Pull Valve | 2" PVC with Unions | 263064
    Pentair 2" PVC Push-Pull Backwash Valve - DE/Sand Filters - 263064

  • Pentair FullFloXF High Performance Backwash Valve For FNS Plus D.E. Filters 2.5"x3" | 263081
    Pentair FullFloXF High Performance Backwash Valve
    FNS Plus D.E. Filters
    2.5"x3" | 263081

  • Pentair Hi-Flow Multi-Port PVC Backwash Valve for Side Mounted  D.E. Filters | 261142
    Pentair Multi-Port HiFlow PVC Backwash Valve - DE Filters - 261142

  • Pentair 1.5" & 2" Threaded Adapter Kit | 271096
    1-1/2 & 2 in. Threaded adapter kit for installations without valve | 271096 (Good)

  • Waterco MultiCyclone 50 Pre-Filter 2-Inch | 200375 200370
    Waterco MultiCyclone 50 Pre-Filter 2-Inch | 200375 200370

  • Fiber Clear Cellulose Powder Filter Media | Replaces Diatomaceous Earth | 3 lbs. | FCR-048B
    Fiber Clear Powder Filter Media | Replaces D.E. | 3 lbs. | FCR-048B

FNS® Plus Filters are fiberglass reinforced polypropylene of advanced chemical resistant materials for superior strength and reliability. The top manifold design features the Service-Ease grid pack for convenient one-at-a-time grid servicing. Filtering with diatomaceous earth (D.E.) gives you water that really sparkles. That's because D.E. filters remove the tiniest of contaminants¦particles as small as 5 microns. (An average grain of sand is 1000 microns!) Even though these particles can't be seen individually, collectively they greatly affect water clarity.

Diatomaceous earth filters work so well because water passes through a series of D.E. coated grids. Under a microscope, D.E. looks like a collection of tiny sponges. And just like a sponge, water can pass through, but microscopic impurities like dirt, algae, and some forms of bacteria can't.

FNS® Plus D.E. Filters have been designed with curved grids to maximize filtration area. More filter area means better performance and longer periods between cleanings. Our exclusive internal design has been refined to minimize fl ow restrictions, and therefore requires minimal pumping power to achieve a needed fl ow rate. That means lower utility costs.

In addition to providing the clearest possible water, FNS Plus was also designed for easy maintenance and long-term reliability. So you can count on it to keep your pool's water clean and crystal clear for years to come.
  • Curved vertical grids provide maximum filter surface area for greater dirt-trapping capacity and longer periods between cleanings.
  • Unique internal design ensures optimum filtration and backwashing efficiency.
  • Chemical resistant, fiberglass reinforced polypropylene tank for exceptional strength and long life.
  • Easily removable filter grid pack to simplify maintenance and save you time.

Brand: Pentair
Square Foot
Grid Type
Q & A
Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 20 questions Browse 20 questions and 17 answers
Does this come with the filter elements or is this just the shell?
A shopper on May 14, 2017
BEST ANSWER: This item comes with the filters but as is normal, it does not include any valves that attach to the outside of the filter unit in order to divert the water flow.
I have a 24 square foot Pentair D E filter for a 20,000 gallon pool. Is this the right size?
James K on Jun 1, 2018
BEST ANSWER: 20,000 would be the max for the 24 so you should go up one size in my opinion. My pool is 20,000 and I got the FNS 48.
I have a 45,000 gallon pool is this the correct size?
paul l on Apr 23, 2020
i want to replace DE filter with sand filter what size sand filter would i need?
A shopper on Apr 13, 2016
BEST ANSWER: From what information I have, I can't tell you what size filter you need. I would advise you to speak with a pool professional. Discuss your needs, the concerns you have in making the choice - size and type - because the available technology provides a variety of choices. Having said this, I will tell you that I am very happy with my choice of the Pentair DE filter and having chosen pool supply unlimited.
Charles C on Aug 13, 2017
BEST ANSWER: The about of D.E. that needs to be used for a 48sqft is 5lbs per the manufacturer.
Hello, checking availability on a 48 ft.² FNS plus?
A shopper on Mar 29, 2021
Pentair Fiberglass D.E. Filter, FNS Plus | 48 Square Feet will be enough for 25000 gallons inground pool?
Andre on Nov 30, 2019
BEST ANSWER: I have a 28,000 gallon pool and my 48 Square Feet DE Filter has worked well for 19 years. I have replaced the unit only once after the initial 18 years. I’ve replaced the filters 3 times during the original 18 years. Great filter system, water is crystal clear.
how do you deterine what size de filter you need?
A shopper on Feb 1, 2020
BEST ANSWER: Checkout our blog post on choosing the right size pool filter:
I have a Pentair FNC Plus 48 DE filter part number 190029. Is this the same one, part number 180008?
A shopper on Aug 22, 2019
BEST ANSWER: 190029 is not a current Pentair part number. How old is your filter? It is possible that you have a FNS 48 filter, made about 10-20 years ago. If so, it is similar to the FNS PLUS filter, part number 180008.
Can it be used with salt water system?
A shopper on Aug 31, 2021
Currently in stock-Pentair EC -180008, 48 sq ft FNS Plus DE filter?
A shopper on Aug 26, 2021
my pool is 40.000 gallons, Ii have a DE Quad 100, Will this be the right replacement?
A shopper on Aug 22, 2021
is this currently in stock?
rick w on Aug 2, 2021
is it in stock?
A shopper on Jun 14, 2021
Is this in stock?
A shopper on May 31, 2021
can I purchase this without the filter grid?
John T on Apr 6, 2021
I need a 60 fns Tifton nautilaus tank. 40000 gallons 2 hp motor 125 gpm?
David on Aug 10, 2020
I have a 45,000 gallon pool is this the correct size?
A shopper on Apr 23, 2020
4.8 / 5.0
13 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Rated 4 out of 5
Tank is not warranted unless its professionally installed.
My previous filter had lasted the entire life of the pool from when it was built. The directions for this one were easy to follow, packaging was great and delivery was quicker than I expected. The one thing that I was very disappointed about is that Pentair will not warrant the tank if it is not installed by a qualified installer. Understandable I guess?
September 5, 2015
Rated 4 out of 5
The only problem I encountered with filter was the match up with the multi-valve fittings. There is a height difference between the older Pentair/Nautilus D.E. filter and newer Pentax filter. Found landscape pad at Home Depot to raise new filter up to match valve fittings.

Filter works great.
August 20, 2016
over 6 years ago
Rated 5 out of 5
Pentair filter
Pentair is a great brand. Easy to install...I installed it myself, then cleaned the pool...water is sparkling! I have bought other products and they are all of great quality. I would definitely recommend
November 12, 2019
over 2 years ago
Rated 5 out of 5
Came as described, with cartridges installed I needed to install the breather and gauge, which went together as they should. Put next to valve and screwed everything up and turned it on, no leaks, worked as it should and very happy from start (ordering to finish) to finish with company and fns filter. Mind you that it replaced a 16 year old unit that sits in direct sunlight, so I'm expecting the same with this one.
June 8, 2020
1 year ago
Rated 5 out of 5
Installation of Pentair D.E. Filter
The filter was received in a timely manner and was very easy to install. I had never installed one before but it was very logical as per the instructions. I would have no problem suggesting that anyone can install the filter.
August 19, 2016
over 6 years ago
Rated 5 out of 5
Working great! Arrived within days, earlier than expected:)
September 29, 2020
1 year ago
Rated 5 out of 5
Fast delivery, works flawlessly
Very happy with the FNS plus 48. This is a replacement for a prior one that I had that lasted several years. I was delighted with how quickly it arrived.
September 7, 2020
1 year ago
Rated 5 out of 5
So far the filtration system works great and I can get very clear water. Either a filtration system works or it doesn't. This DE filter works great for a 1.5 - 2 hp pool pump. Thus far (3 months in) the fiberglass body holds up, as do the seals, manual pressure gauge, etc. Great product.
June 9, 2020
1 year ago
Rated 5 out of 5
Works perfect, installed easily. Happy with the product and the purchase experience. Will always purchase from Pool Supply Unlimited.
April 14, 2020
over 5 years ago
Rated 5 out of 5
So far I'm very happy with the service and the unit, that I received! Thank you very much!
May 14, 2018
over 3 years ago
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Register your Pentair product online at www.pentair.com.

You've always been able to count on the quality and long service life of Pentair products. Pentair uses state of the art workmanship, materials and manufacturing processes to create the most innovative pool and spa equipment anywhere. And now Pentair products can deliver even more value and peace of mind, because Pentair offers extended warranty coverage on select products that are installed by a qualified installer*.
While the majority of Pentair products are covered by a sixty- (60) day warranty, a select number of products qualify for extended warranty coverage.
Select Bundled Products: applies to purchases and qualified installation of a minimum of a pump and filter, and one or more of the following: heaters, heat pumps, control systems, automatic cleaners, lighting, salt chlorine generators or UV sterilizer**
*Note: Qualified Installer - Defined as a licensed professional who charges a fee for his services, and possesses a business license, contractor's license and/or resale permit. Common examples of a "qualified installer" include: Swimming Pool, Home Repair or Landscape Professional; Plumber or Electrician; General Contractor; Heating and Air Conditioning Specialist.
**Note: Bundled products - must be purchased on the same invoice and installed at the same time. If any product within a bundle is ineligible for the bundled warranty coverage then all products within the same bundle will be disqualified from receiving the three (3) year extended warranty coverage for bundled products.
TradeGrade products must be purchased from a retail store (brick & mortar), pool builder or pool service company to receive a one-year, two-year or three-year warranty. If purchased online will only receive a sixty-day limited warranty. View the list of TradeGrade Products.
Ecommerce (EC) products: Products purchased from an Authorized Pentair Online Reseller (products beginning with EC-) receive a one (1) year (parts only) warranty from the date of purchase. The exceptions are: IntelliChlor cells and IntelliFlo SVRS pumps which receive a two (2) year warranty. EC products are not eligible for the bundled three (3) year extended warranty.
Visit www.pentair.com to submit your product warranty registration.
This information was updated on 11/19/2021. For the most current information and full warranty policy please visit www.pentair.com/warranty.

 Adobe Acrobat PDF Warranty Information
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