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Your cart is empty. 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 20 (long) – 29 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.
As water continues to be drawn through, anaerobic bacteria collects and colonizes within the gravel and filter plates.
PLEASE NOTE: Color of Under-Gravel Plates may differ from the images.
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
2 Filter Plates
2 Adjustable Lift Tubes
2 Straight Airline Tubes
3 Filter Plate Connecters
2 Replaceable Filt-a-Carb Activated Carbon Media Cartridges
Measurements:
Each Filter Plate Separately = 14” (W) x 11.1” (D)
Filter Plates Together = 28” (W) x 11.1” (D)
Each Lift Tube at Filter Plate Base = 13” – 16”
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.
JASON TICE
Reviewed in the United States on May 18, 2025
good and fast delivery
Roslyn A.
Reviewed in the United States on March 9, 2025
The instructions didn’t help much! However I looked it up on YouTube, watched a video and it helped me extremely well with putting it together. It works really good and not noisy!
Joseph
Reviewed in the United States on March 22, 2025
I swear this helps make tank maintenance so much easier, super easy to set up and it keep a the tank clean!
J. Huffman
Reviewed in the United States on January 3, 2025
The plates can be connected and must be connected for power head use. To do this you have to pop out some plastic sections which is quite a chore. Also, the up spouts are too short for a power head on a 20L so I had to trim mine down, but that was easy. But the unit seems well made and is not made of that really brittle plastic that breaks easily.
Alan Gordon
Reviewed in the United States on July 2, 2024
Lee UGFs' are the best on the market and I use them on freshwater. saltwater and brackish [such as cichlids]. it is easy to set up, but you want to use power heads and knock out the tabs on underneath side to have a flow thru plate design, so the 2 plates work like 1 and no dead spots .You could block 1 tube off [ Amazon sells caps to do this] and just use 1 power head and with the flow thru set up it will still work correctly. The benefits such as when the fish kick ammonia out of their gills, the power head[s] make slight suction and pull it through the substrate to the UGF where bacteria attached to the plastic eat it, also it keeps the lift tubes clean because water is moving all the time and the power head[s] create current that the fish are use to. This the ideal set up and the way it was designed to work. Don'i run the power heads in reverse because it pushes the ammonia away from the UGF , so your fish are swimming in their own pee, not a good environment. Air stone version can not do any of these benefits because they were not designed to and in some cases nitrogen dioxide forms in UGF which bacteria is killed off, so you have dead plates. With power head[s] and flow thru plates it provides sufficient circulation of oxygen in the UGF displacing it , solving the problem. I tell you this because I want your fish to live and be happy. Since your water is cleaner ,less water changes are needed !
Steve Ma
Reviewed in Australia on November 20, 2024
Arrive on time. Great quality item
Sam Savill
Reviewed in Canada on November 4, 2023
The best filtration method there is.I supercharge mine by fitting PVC pipe section into the bottom locking pipe (which is cheap and brittle - man up and fix that Penn-Plax) and attach a powerhead to the lift tubes. Add a bottom matten filter of 30ppi sponge foam and you have MASSIVE filtration surface.Real aquarium owners use Under Gravel Filters religiously. Stop wasting your money on replacing filters - "filters" are for surface area for beneficial bacteria to grow on that cleans your water & eats ammonia, nitrites and disease pathogens.It saddens me how people fall for the new, shiny junk that just keeps costing them time and money - these things work GREAT
FT
Reviewed in Canada on April 3, 2023
I had to modify it in order to get the correct flow under the grid.
R. Peeples
Reviewed in the United States on October 18, 2022
If you have an aquarium, an undergravel filter is a necessity! They are simple and you don't really see them working, but they are vital to the health of your aquatic life. While it does take a few weeks for the bacteria to start feeding on the food and other waste that gets sucked into the filter, a UGF will definitely help keep the water clean. I have only had one aquarium over the years that did not have a UGF and it was the only one that I ever had problems with. You can add a hang on back (HOB) filter to have extra filtration, but it is the UGF that's the workhorse of the system. Nearly all of the complaints I see from people are the ones that don't understand how it works. They don't give it enough time to start working. Even when using aged water and bacteria from another aquarium, it still takes time. BUT once it reaches the point of where the bacteria start to increase, you don't have to do anything else to it. It normally takes a few weeks for this process to start. You can add fish and such before the UGF begins to work, so this is where the HOB would be good to use. At the most, I have vacuumed out the extra waste maybe once every six months - not all of it, just some of it. Again, the key is to give it time to work. Patience is what is called for.As for the Penn-Plax brand, it is really the only brand to consider. The price is right. The quality is good. Penn-Plax has it dialed in. The only thing I don't do is to use the carbon attachments. I have found that they are not needed at all. I wish Penn-Plax would leave them out and lower the price a few dollars.
Sherbs
Reviewed in Canada on January 2, 2022
I have had these types of filters before and they work great. Not sure why they are not as common as sponge, unless it is because of fish rooms with bare bottom tanks. This filter is well built and comes with adjustable height stand pipes. Put it in a 33 gallon tank and it doesn’t quite fill up the bottom as the 3 foot tank is longer than it is meant for, but it covers enough to be effective for my use. The two bottom blue filters can be used independently or clicked together with provided plastic clips.
Green girl 87
Reviewed in the United States on September 8, 2017
Exactly as it is supposed to be. Fyi, this comes with 2 uplift tubes. That info wasn't in the description. Also not in the description is the info that it comes with 2 filt-a-carb cartridges to go in the top of the tubes. Although if you zoom into the pic of the item, you can see that info written on the package. And just a note, if you want more uplift tubes, I suggest getting the penn plax brand. Because of the way they connect to the plate, lee's brand doesn't really work. I mean, you can do some creative rigging and probably make it work. But it would just be a lot easier to buy ones made for this system.And it comes with these little rectangular pieces with a hole in the middle. You may wonder what they are for. They are to connect the 2 plates together. See pics. But in order to do that you have to break out the in between pieces, which aren't scored very well, making it quite difficult. I recommend having a utility knife handy to score them a bit more.And finally, if you want this for a 20 gallon long instead of a 29 gallon, the uplift tubes will be way to long. You can actually cut one in half and those 2 pieces will be enough. I just used a small hand saw to cut mine. Though you can probably do it with a utility knife.Update: At first I didn't like the design of the uplift tubes. They have these thin rigid straw like things that go down them that you connect the airline tubing to on top and airstone with small section of tubing on bottom. I had ordered some zeolite cartridge elbows anyway so I used those with airline tubing running the length of the uplift tube to the airstone. But I'm about to start medicating my fish, and I know you have to take carbon out, didn't know if zeolite was the same. So I thought better safe than sorry and took the zeolite elbows off and put originals with the plastic straw like thing on. They were also too tall for a 20 long tank, and I had to cut them in half just like the uplift tube. But I can tell you I think they are going to work out. 1. It is a lot easier to pull that straw thing up and connect an airline to it than it is connecting to the top of the zeolite cartridges. 2. It uses less length of airline tubing. About 7 or so inches in my case. But if you were using on a 29 like the kit is designed for, it would be about 15 inches. Per tube, meaning I'm saving a total 15 or so inches on my 20 long and you'd save over 30 inches on a 29 gallon using 2 uplift tubes. That is a lot of tubing! And I know tubing is pretty cheap, but still, waste not want not. 3. I was concerned that the inside of these straw like things would get grody just like airline tubing does, and I wouldn't be able to clean them. As it turns out, you can get a small enough diameter straw cleaning brush for them. That isn't to say it won't be a pain. But it is possible.
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