Customer Reviews

Rating: 3.6 of 5 stars 32 Reviews 32 Reviews 3.6 out of 5 Stars

88% Recommend

88% of reviewersrecommend this product

Rating: 3.6 of 5 stars 3.6 / 5

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Penn-Plax Premium Underground Aquarium Filter

Penn-Plax Premium Underground Aquarium Filter

  • Most Helpful Positive Review

    Read All 20 Positive Reviews

    filters and use

    By fishy on Jan 15, 2022

    these work great use lift tube on one end connected to canister filter other end a power head or 2 power heads use corner filters for bio and chemipure or canister. i have had a tank that only needs filter maint. and add water for over a year. shoot the flow direction of filter and powerhead at front these work great use lift tube on one end connected to canister filter other end a power head or 2 power heads use corner filters for bio and chemipure or canister. i have had a tank that only needs filter maint. and add water for over a year. shoot the flow direction of filter and powerhead at front center of tank to cross flow creating turbulent flow. other than monthly lite vacuming and keeping either the canister retun or powerhead above water at least .5 inch for airation for amonia pretty maint free note use boyds chemipure. … more

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  • Most Helpful Critical Review

    Read All 12 Critical Reviews

    Undergravel filter not the best

    By Notgood on Apr 9, 2022

    This filter is ok, but not as good as my old one. The fish waste sits on top of the gravel; and accumulates on the edges of the tank. I have 6 fish in a 35 gallon tank; so I don't have an overcrowded tank by no means. zebra danios and one Pleco.

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32 Reviews

Showing 1-10 of 32 Reviews

  • 1 out of 5 stars

    Undergravel filter not the best

    By on

    This filter is ok, but not as good as my old one. The fish waste sits on top of the gravel; and accumulates on the edges of the tank. I have 6 fish in a 35 gallon tank; so I don't have an overcrowded tank by no means. zebra danios and one Pleco.

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  • 5 out of 5 stars

    filters and use

    By on

    these work great use lift tube on one end connected to canister filter other end a power head or 2 power heads use corner filters for bio and chemipure or canister. i have had a tank that only needs filter maint. and add water for over a year. shoot the flow direction of filter and powerhead at front center of tank to cross flow creating turbulent flow. other than monthly lite vacuming and keeping either the canister retun or powerhead above water at least .5 inch for airation for amonia pretty maint free note use boyds chemipure.

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  • 4 out of 5 stars

    PENN-PLAX UNDERGROUND FILTER

    By on

    THE ITEM IS A GREAT UNDERGROUND FILTER, BUT, WHEN ARRIVED AND OPENED, THE ONE PIECE THAT THE CHARCOAL FILTER PART SLIDES INTO WAS BROKEN ON THE BOTTOM UPON TAKING OUT OF THE PACKAGE. I HAVE IT CURRENTLY TAPED UP TO BE ABLE TO USE IT AS I HAD THE FILTER ALL SET WITH THE STONES ON TOP IT BEFORE I PUT THOSE LAST PIECES ON.. AND MY GRANDSON WAS NOT HAPPY I HAD TO TAKE HIS TURTLE TANK APART AGAIN.

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  • 5 out of 5 stars

    Penn=Plax underwater gravel filter.

    By on

    I always use an underwater gravel filter along with a sponge filter and a HOB filter. Each type of filter does its thing and my tanks stay clean and clear longer and the nitrogen cycle is kept intact by using more than one filtration system that supports it.

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  • 5 out of 5 stars

    Great addition to aquarium

    By on

    Updated my 20 gallon tank and added this ungravel filter. 10+ years ago they were popular and I used one and enjoyed it. Fast forward to this tank now, they were not easily found in store or online. 4+ years now, I updated my tank and found this on Chewy, it made a difference in aesthetics, less tubing but more air flow.

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  • 1 out of 5 stars

    Not for me!

    By on

    Followed the directions , this is not for me. It doesn't work .

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  • 4 out of 5 stars

    Not super sturdy but they work

    By on top1000Contributor

    The Penn-Plax Underground filters work just fine. They aren't exactly flimsy but they aren't nearly as sturdy as some other brands so you have to be aware of that when installing them. But they don't cost near as much either. And the plates are completely flat, which some filters aren't. I would not suggest them for use in salt water tanks but they are a good buy and they work.

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  • 3 out of 5 stars

    Can't buy replacement filters through Chewy.

    By on

    I love the filter. Fits great in my 10-gallon tank was very easy to assemble. BUT Chewy does not sell the replacement filters!

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  • 5 out of 5 stars

    Super Filter

    By on

    After lots of online research, some people either love or hate under gravel filters. Personally, I think it’s a great set up for any tank. I liked it because of the lower water flow compared to a power filter. I wanted fish who like less flow: Betta, Guppies, Mollies. I also did an aquatic plant and just planted it in a little terra cotta pot with gravel. This system works by using the air bubbles in the lift tubes to create suction through the base plates under the gravel. When the solids are pulled through the gravel to the base of the tank, beneficial bacteria is able to digest and break it down. I still plan on doing water changes each month and using a gravel vacuum to suck up additional After lots of online research, some people either love or hate under gravel filters. Personally, I think it’s a great set up for any tank. I liked it because of the lower water flow compared to a power filter. I wanted fish who like less flow: Betta, Guppies, Mollies. I also did an aquatic plant and just planted it in a little terra cotta pot with gravel. This system works by using the air bubbles in the lift tubes to create suction through the base plates under the gravel. When the solids are pulled through the gravel to the base of the tank, beneficial bacteria is able to digest and break it down. I still plan on doing water changes each month and using a gravel vacuum to suck up additional solids. I chose to use a nano air pump with the system because my tank is only 10 gallons and the nano air pump is very quiet. when the solids are pulled through the gravel to the base of the tank, beneficial bacteria is able to digest and break it down. I still plan on doing water changes each month and using a gravel vacuum to suck up additional solids. I chose to use a nano air pump with the system because my tank is only 10 gallons and the nano air pump is very quiet. NOTE: you will need to purchase an air pump and airline tubing separately to complete the set up. I would also recommend a splitter for the air tubing if you’re planning on using one air pump to power the uplift tubes. … more

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  • 2 out of 5 stars

    Some parts were broken

    By on

    Nice setup if my plastic tubes wouldn't of been, cracked and broken kinda disappointed but I'm hoping that I can get a replacement

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