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Penn-Plax Undergravel Aquarium Filter for 40-55 Gallon Tanks – Four 11.25” x 11.25” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater Tanks (CFU55)
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Free returns are available for the shipping address you chose. You can return the item for any reason in new and unused condition: no shipping charges
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Purchase options and add-ons
- NOTHING LIKE OLD SCHOOL: The Clear-Free Premium Under Gravel Filter is air driven and utilizes an Air Pump (not included) to cycle crystal clear water throughout your aquarium, while keeping a crisp and neat look inside. This means there’s less “moving parts,” making for simplistic and easy maintenance. This filter is suitable for most 40 – 55 gallon aquariums.
- BIOLOGICAL, CHEMICAL, AND PHYSICAL FILTRATION: As air is pushed through the Air Stones and rises through the Lift Tubes, water is gently suctioned through gravel and the filter plates, allowing both air and water to pass through the Filt-a-Carb Activated Carbon Cartridges. When water continues to be drawn through, anaerobic bacteria collects and colonizes within the gravel and filter plates.
- ALSO AERATES YOUR TANK: Since the Clear-Free Premium Under Gravel Filter is air driven through the use of Air Stones and an Air Pump (not included), it also aerates your tank. In essence, your aquarium is being filtered and aerated at the same time, though the same system. It’s a filter and bubbler in 1.
- ITEMS INCLUDED: The Clear-Free Premium Under Gravel Filter includes 4 Filter Plates, 4 Adjustable Lift Tubes, 4 Straight Airline Tubes, 9 Filter Plate Connecters, and 4 Replaceable Filt-a-Carb Activated Carbon Media Cartridges.
- MEASUREMENTS: Each Filter Plate Separately = 11.25” (W) x 11.25” (D) / Filter Plates Together = 45” (W) x 11.25” (D) / Each Lift Tube at Filter Plate Base = 13.25” – 16.5”
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From the manufacturer
Suitable for 40 - 55 Gallon Tanks
PENN-PLAX, manufacturer & distributor of top Pet Supplies.
PENN-PLAX is a family owned business that was established in 1956 in Brooklyn, New York. Over the years our goal remains the same: to enhance the pet ownership experience.
We specialize in creating excellent pet supplies for animals, both great and small. We're best known for producing pet products at affordable prices. Our brand, PENN-PLAX, is synonymous with innovation and quality, keeping your pet foremost in mind.
Clear-Free Premium Under Gravel Aquarium Filter
Powerful & Efficient Filtration
PENN-PLAX presents the Clear-Free Premium Under Gravel Aquarium Filter.
Those who’ve been around the aquatic block for a while know that Under Gravel Filters (UGFs) are a testament of time.
This Filter is air driven and utilizes an Air Pump (not included) to cycle crystal clear water throughout your aquarium, while keeping a crisp and neat look inside.
This means there’s less “moving parts,” making for simplistic and easy maintenance.
It’s suitable for most 40 – 55 gallon aquariums.
Take a Closer Look at the Clear-Free Premium Under Gravel Aquarium Filter
Biological, Chemical, and Physical Filtration:
- As air is pushed through the Air Stones and rises through the Lift Tubes, water is gently suctioned through gravel and the filter plates, allowing both air and water to pass through the Filt-a-Carb Activated Carbon Cartridges. When water continues to be drawn through, anaerobic bacteria collects and colonizes within the gravel and filter plates.
Also Aerates Your Tank:
- Since the Clear-Free Premium Under Gravel Filter is air driven through the use of Air Stones and an Air Pump (not included), it also aerates your tank. In essence, your aquarium is being filtered and aerated at the same time, though the same system! It’s a filter and bubbler in 1!
Assembly Instructions:
- To assemble your new filter, simply attach the plates together, assemble the lift tubes, attach the lift tubes to the filter plates, and then add the whole filter to your aquarium. Next, connect each lift tube to an air pump to power the filter. - Air Pump Not Included.
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Customer Reviews |
4.3 out of 5 stars
1,548
|
4.4 out of 5 stars
1,204
|
4.4 out of 5 stars
1,258
|
4.3 out of 5 stars
3,536
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Model Number | CFU10 | CFU20 | CFU29 | CFU55 |
Aquarium Size | 10 Gallon | 15 - 20 (high) Gallon | 20 (long) - 29 Gallon | 40 - 55 Gallon |
Overall Measurements | 19” (W) x 9.5” (D) | 22.5” (W) x 11.2” (D) | 28” (W) x 11.1” (D) | 45” (W) x 11.25” (D) |
Individual Plate Measurements | 9.5” (W) x 9.5” (D) | 11.25” (W) x 11.2” (D) | 14” (W) x 11.1” (D) | 11.25” (W) x 11.25” (D) |
Number of Plates Included | 2 | 2 | 2 | 4 |
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Customer Reviews |
4.6 out of 5 stars
1,625
|
4.6 out of 5 stars
1,625
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4.6 out of 5 stars
130
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4.5 out of 5 stars
55
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Replacement Filter Media Type | Filt-a-Carb Replacement Activated Carbon Media Cartridges | Filt-a-Carb Replacement Activated Carbon Media Cartridges | Ammonia-X Replacement Zeolite Media Cartridges | Ammonia-X Replacement Zeolite Media Cartridges |
Model Number | FC2 | FC3 | AX2 | AX3 |
Number of Cartridges | 2 | 2 | 2 | 2 |
Product guides and documents
Product details
- Is Discontinued By Manufacturer : No
- Product Dimensions : 11.5 x 2.5 x 11.5 inches; 2.02 Pounds
- Item model number : CFU55
- Date First Available : July 6, 2010
- Manufacturer : Penn Plax, INC.
- ASIN : B003UTNOU6
- Country of Origin : China
- Best Sellers Rank: #22,738 in Pet Supplies (See Top 100 in Pet Supplies)
- #257 in Aquarium Filter Accessories
- Customer Reviews:
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Looking for specific info?
Product Description
PENN-PLAX presents the Clear-Free Premium Under Gravel Aquarium Filter.
Those who’ve been around the aquatic block for a while
know that Under Gravel Filters (UGFs) are a testament of time.
This Filter is air driven and utilizes an Air Pump (not included) to cycle crystal clear water throughout your aquarium,
while keeping a crisp and neat look inside.
This means there’s less “moving parts,” making for simplistic and easy maintenance.
It’s suitable for most suitable for most 40 – 55 gallon aquariums, and is safe for Freshwater and Saltwater setups.
Biological, Chemical, and Physical Filtration:
As air is pushed through the Air Stones and rises through the Lift Tubes,
water is gently suctioned through gravel and the filter plates,
allowing both air and water to pass through the Filt-a-Carb Activated Carbon Cartridges.
When water continues to be drawn through, anaerobic bacteria collects and colonizes within the gravel and filter plates.
Also Aerates Your Tank:
Since the Clear-Free Premium Under Gravel Filter is air driven
through the use of Air Stones and an Air Pump (not included), it also aerates your tank.
In essence, your aquarium is being filtered and aerated at the same time, though the same system!
It’s a filter and bubbler in 1!
Items Included:
The Clear-Free Premium Under Gravel Filter includes
4 Filter Plates
4 Adjustable Lift Tubes
4 Straight Airline Tubes
9 Filter Plate Connecters
4 Replaceable Filt-a-Carb Activated Carbon Media Cartridges
Measurements:
Each Filter Plate Separately = 11.25” (W) x 11.25” (D)
Filter Plates Together = 45” (W) x 11.25” (D)
Each Lift Tube at Filter Plate Base = 13.25” – 16.5”
Shop PENN-PLAX for All Your Pet’s Needs:
PENN-PLAX is a manufacturer and distributor of top quality pet supplies,
who specialize in creating excellent pet products for animals, both great and small.
Important information
Directions
Wash with warm water before placing in aquarium.
Compare with similar items
This Item Penn-Plax Undergravel Aquarium Filter for 40-55 Gallon Tanks – Four 11.25” x 11.25” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater Tanks (CFU55) | Recommendations | dummy | dummy | dummy | dummy | |
Try again! Added to Cart Add to Cart | Try again! Added to Cart Add to Cart | Try again! Added to Cart Add to Cart | Try again! Added to Cart Add to Cart | Try again! Added to Cart Add to Cart | Try again! Added to Cart Add to Cart | |
Price | -19% $28.99$28.99 List: $35.99 | -29% $44.99$44.99 List: $63.59 | -28% $10.04$10.04 Typical: $13.85 | -8% $48.99$48.99 List: $52.99 | $14.99$14.99 | $11.45$11.45 |
Delivery | Get it as soon as Tuesday, Apr 2 | Get it as soon as Tuesday, Apr 2 | Get it as soon as Tuesday, Apr 2 | Get it as soon as Tuesday, Apr 2 | Get it as soon as Tuesday, Apr 2 | Get it as soon as Tuesday, Apr 2 |
Customer Ratings | ||||||
Value for money | 4.1 | 3.2 | 4.1 | — | 4.6 | 4.0 |
Easy to use | 4.2 | — | 4.0 | — | 4.8 | 3.9 |
Easy to assemble | 4.0 | 4.2 | 4.2 | — | — | 4.0 |
Easy to install | 4.1 | — | 4.5 | — | — | 4.3 |
Suction power | — | 3.9 | 4.2 | 4.6 | — | — |
Sold By | Amazon.com | Amazon.com | Amazon.com | Amazon.com | Amazon.com | Amazon.com |
Customer reviews
Customer Reviews, including Product Star Ratings help customers to learn more about the product and decide whether it is the right product for them.
To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyzed reviews to verify trustworthiness.
Learn more how customers reviews work on AmazonCustomers say
Customers like the performance, ease of assembly, and value of the pet supplies. For example, they mention that it works well, the instructions are easy to follow, and the price is great. They also like the filter, and appearance. That said, some complain about the quality, saying that the tubes are cracked and the plastic breaks easily. Opinions are mixed on cleanliness and fit.
AI-generated from the text of customer reviews
Customers generally like the performance of the pet supplies. They say that it works well once configured, and is a good running system. Customers also mention that the sharp scissors work just fine.
"Good product" Read more
"...I say basic because these are so simple and easy to use and very effective.These are huge biological filters...." Read more
"...Good then and good now." Read more
"...Sharp scissor well work just fine. I have two sets kin my 125 gallon tank, make sure to keep the ends closed though...." Read more
Customers find the pet supplies easy to assemble. They mention the instructions are easy to follow, and the product is simple and easy to use. Some say it's perfect to help with the entire setup.
"...It was pretty easy to set up. Once you kind of figure out how the first tube together it was easy set up...." Read more
"Wanted a planted tank. These are perfect to help with the entire setup. So far it's been a month and I've not had to change anything!..." Read more
"...The product was easy to assemble and came neatly packaged. This is not a seller issue...." Read more
"This is a GIANT pain to install and clean plastic tubes. The filter cartridges are expensive, and I don’t believe there is a way around it...." Read more
Customers like the value of the pet supplies. They say it's a great product for the price, works excellent, and is a nice buy. Customers also mention that the materials and design are excellent for the value.
"I knew this item wasn't going to be anything special, it is a great price after all...." Read more
"Was a good price for a 55 gallon undergravel filter. Supports the gravel and rocks well and has not broken a panel. Seems to be well made...." Read more
"...work so we just have bubbles coming out of that one but it was okay for the price" Read more
"...The filter cartridges are expensive, and I don’t believe there is a way around it. If you are using on a small tank, it could work better for you...." Read more
Customers like the filter. They say it's a great filter for aquariums, it filters the water well. Some customers also mention that it does a little more filtering than other filters. Overall, customers are satisfied with the quality and functionality of the filter, which makes it a good choice for setting up a biological filter for your aquarium.
"...This filter won't create waste for land fill, won't fail spectacularly, won't require you to keep the filter companies profits afloat, but it will..." Read more
"...These are huge biological filters...." Read more
"...Penn-Plax was the go-to 35 years ago, and still produces a quality under gravel filter. Good then and good now." Read more
"...they are more natural way to filter the water. it allows you to enhance it with other filter systems like canister or otb filter...." Read more
Customers are satisfied with the appearance of the pet supplies. They mention that the underground plates are well designed with support stems strategically placed. They also say that it keeps the tank cleaner and more vibrant.
"...But it looks nice and my turtle does seem to enjoy it. So overall, it has its ups and downs." Read more
"...debris settles and collects under the panels well and keeps the tank cleaner looking." Read more
"It’s nice. It’s a pain in the butt to put together the directions don’t do it that well. I just watching a YouTube video...." Read more
"...These come with more than enough lift tubes. Great item to keep your tank looking great." Read more
Customers are mixed about the cleanliness of the tank. Some mention that it does a great job keeping their tank clean, and the water is staying much cleaner. However, others say that it doesn't keep the tank clean and that it leaves a lot of debris at the bottom.
"...It does a really good job of keeping the sediment under the grate so it’s not on the rocks at all and doesn’t get stirred up by the fish...." Read more
"...Extra work to make it work, extra work to keep it clean, extra money spent...." Read more
"Makes cleaning easier" Read more
"...No gravel cleaning.Contrary to popular belief, they NEVER GET CLOGGED. EVER!Yes, you can have a planted aquarium...." Read more
Customers are mixed about the fit of the filter. Some mention that it works great and is a perfect fit for their 55 gallon tank, while others say that it didn't fit their tank and the multiple plates together didn''t work well.
"The filter fit my tank perfectly...." Read more
"I bought this product for my 36 gallon bowfront naturally it doesn't fit well so a lot of cutting and rearranging is needed...." Read more
"...once assembled and placed, it blends into the tank wellit fits well in the tank, covering the whole bottom...." Read more
"...The second star was removed as the riser tubes are not as long as they should be or once were...." Read more
Customers are dissatisfied with the quality of the pet supplies. They mention that the plastic breaks very easily, the tubes and filter heads are broken, and the ridged plastic is brittle. Some customers also say that the first order was damaged and the plastic is just become frail.
"...I repeatedly had issues with stuff building up in the tube I was able to get a brush and clean out a lot but not at the very bottom.. my tank is..." Read more
"...were made of a very ridged plastic, This was a bit brittle but posed no issues after they base was installed...." Read more
"Well made under gravel filter. I used it in a 40 Gallon tank I'm just starting to set up...." Read more
"I would have given 5 stars, but my first order was damaged, i.e., the heads and tubes were cracked. I sealed the cracks, so it is functional...." Read more
Reviews with images
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Top reviews
Top reviews from the United States
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Once a very popular filter, actually it was considered the best at the time, it is now frowned upon and is no longer considered the best filter to use. This is not because the filter is not great at what it does, its just that the definition of "best" has been refined for modern times. "Best" is now defined by a product that requires regular purchase of filter media to get the "best" profits for companies producing them. They are also "best" at wasting resources and adding to landfills. They are also "best" at unreliability being at about five years or so.
So if you want the "best" available today in terms of all those things, don't get this.
This filter won't create waste for land fill, won't fail spectacularly, won't require you to keep the filter companies profits afloat, but it will filter your aquarium crystal clear for decades without issues or monthly costs. Just understand how they are meant to be maintained (leave them alone!) and you are good to go.
The reasons I like UGF over HOB or canisters: Nothing matches the filtering capacity of your entire aquariums bottom for mechanical filtering, and as the void under the gravel is where the good bacteria live, you'd be heard pressed to find any other type with the surface area of the UGF for bio-filtering too.
The carbon filter at the top are cheep, easy to replace and if your so inclined, can be replaced for a power head or even opened up for replacing with new carbon (not intended to be used as such, but were all tinkerers here, right?)
What I dislike about UGF: Over time the bottom can, theoretically, become backed-up with waste. If you overfeed or don't have plants which can consume some of this, it can back-up quicker. However, a gravel vac can remove most of this while doing water changes and in my experience, I've gone many years before I've needed to remove the UGF, usually I only remove it and clean when I get tired of the tank set up and wish to redo the tank.... and even then, I do it not because it's needed, but because I'm in there already. This is maybe not a dislike, but as it's not easy to do, I list it under dislikes.
Over time the tubes usually discolor, become dirty or the like, so over time they will need to be pulled out and cleaned. This isn't hard to do, but it a bit more involved than cleaning a HOB, but is mostly for athstetics, unless the tubes got too dirty and cause a blockade after years of use.
The final item is by far the biggest and only real dislike I have for them, and should serve as a warning for others, with a fix at the end. If you have a tank where the fish breed, the eggs can get pulled into the gravel and wind up at the bottom of the tank, under the gravel. The eggs hatch and now you've got fry swimming under the gravel, had this happen to me. As designed, there is no way for those fry to get out of the system, as the gravel is overhead (can't borrow through that), and the path to the tubes is blocked off even if they could somehow get through the carbon filter (they cant). So this was the reason I stopped using them many years ago. Was the only reason I stopped using them. Now, to fix this...... The plates each come with 2 spots to put tubes in, most likely you will not use or need all of those spots. Each plate is connected below (when knock outs are removed), so fry can swim between them, simply cut one of the unused riser tubes sections out and insert a use in it's place as an escape. I used some tubes I had laying around to do this, but I leave the top capped as to not create other issues. If I see fry swim up the tube (which they will), simply open it and let them out. While this is an issue, it's kind of a double edge issue.... bed they get trapped, but as they are trapped with nutrients below they are not food for others..... have had more than a dozen live down there before and go one to reproduce themselves. How many I lost before this fix... I don't know.
On to the 3 star ratting. This is a reflection on Penn Plax build quality and changes.
The "old school" design (brown plates vs blue) were made of a very ridged plastic, This was a bit brittle but posed no issues after they base was installed. These new blue plates are about 3 steps backward.
Since they are not ridged, they sag from the weight of the gravel on them and even have give from just the riser tubes installed.... 2 issues the older design, which I still have, does not suffer from. Only time will tell if this leads to more than just crooked looking tubes after it's installed, but the fact the tubes are crooked for some might be enough to avoid/return this.... I almost did, but I have plants to cover it and added rock under it to help stiffen it up.
The second star was removed as the riser tubes are not as long as they should be or once were.
I have a 49 gallon bow front, on all my old UGF's the tubes rise high enough to bring the top of the heads just out of the water a bit, making it perfect to filter and reduce the gurgling noise. This new design leaves the tubes 2+ inches below the surface while fully extended and as such you get the bubbling/gurgling noise.
I do love UGF's, but I do not know that I could recommend these over the other brands out there now-a-days. In the past, it was Penn Plax hands down, but with these 2 issues, I feel I will try another brand when I set up another tank if these are not fixed before that time.
Hope this helps anyone looking for an UGF.
Top reviews from other countries
Allerdings: Die Filterkartuschen sollten angeblich alle 2 Wochen getauscht werden. Aber wtf kann man die kaufen??? Von Amazon werden sie nicht an meine Wohnadresse geliefert und wären außerdem teurer als das Gesamtset!!! Scherz oder???
Fazit: Gutes Produkt aber trotzdem überlegen, wie es dann weitergeht ...
So far working great. I have canister filters, sponge, and hang on the backs. For some reason this under gravel filter makes the water look the most clear. I believe benefits bacteria will thrive because of the huge surface area.
PROS: very clear water. Handles debris just as effectively as other filters. Air atone works really good. Good for plants as waste is held under gravel for plant roots to maximize on.
CONS: have to pretty much dismantle the tank to set it up. Parts seem a little cheaply made, but not too bad, and I must say they are all working fine and haven’t given my any issues.