Whisper 20 Power Filter - Up to 20 gal.

7 Reviews
SKU: 247240
Manufacturer: Tetra
MPN: 25772

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Quiet, economical filtration performance of the classic Whisper20 Power Filter is great for freshwater or saltwater aquariums. Energy-efficient designs feature low-wattage motors and adjustable flow control. Bio-Foam cultivates and maintains a bacterial bed for biological filtration, while easy to replace Bio-bag cartridges take care of chemical and mechanical filtration. Bio-Bags included. Measures: 7 in. x 3.5 in. x 7 in. The Whisper 20 is rated for aquariums up to 20 gallons, and has a maximum flow rate of 105 gph.

For more information about the Tetra Whisper 20 Power Filter, see the Manufacturer's Instruction manual.

For more info on Hang-on Power Filters, please see Power Aquarium Filter Basics.


Includes MediaLarge Bio Bag Cartridge
Flow Rate105 gph
Power Cord Length6 ft.
Warranty2 year Warranty
UL ListedYes
Max Tank Size20 gal.
Length7.25 in.
Width4 in.
Height7.25 in.
Internal Id


Click here to download the instruction manual from Tetra's website.

Ratings & Reviews

7 reviews

Excellent flow and quiet too.


I already own a junior one for my 5-1/2 gallon quarantine tank and have no issues. I bought this one for my newly set up 10 gallon tank and have no issues with it. It is very quiet in operation.

Best filter on the market


I have 5 aquariums of varying sizes, and have kept fish for a very long time. Over the years I have tried a variety of different filters, and this is the best, by far. I use this size in a 10 gallon tank, and it keeps the water crystal-clear, and is quiet, efficient, and durable. I will never try another brand - this is the best!



Got this for my 20gal tank and it works great water is clear , It's super quiet and you can choose the flow...great filter

Good Filter


I needed to step up my current Tetra filter and am using this one for my 10 gallon tank. I've always used Tetra filters and this one is good for the cost.

Real Review


While you may believe this is a great filter, it is not packaged with the correct impeller with intake tube. I needed two deliveries from Tetra to make it right. I will not buy another Tetra product.

Whisper does not work


Something is wrong with the tube as it does not seem to fit properly. As a result, it does not function and is extremely noisy. I have spent more of my time with this than it is worth, and now I have to spend more to return it.

Whisper now works


At first I was very upset because the tube didn't seem to fit properly and it was extremely loud. But after I pushed the tube all the way down, it now works and is whisper quite.