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Tetra

Tetra Whisper In-Tank Filter 40i with BioScrubber - 20-40 gallon (25818), Black

    • Based on 19,259 reviews
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Availability: Only 4 left in stock, order soon!
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Arrives Wednesday, May 22
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Size: Up to 40-Gallons


Features

  • UNIVERSAL DESIGN: Tetra Whisper 40i Internal Filter is an all-in-one air pump and water filter system.
  • INTERNAL FILTER: Mounts on the inside of your aquarium with clip (included).
  • CATCHES DEBRIS: Dense, dual-sided mesh filters debris and fish waste.
  • AERATES WATER: Air-driven design filters up to 170 GPH while oxygenating water.
  • CONVENIENT DESIGN: Uses large easy to change Bio-Bag cartridges; filter mounts inside aquarium, making it possible to place tank flush against the wall.

Description

The Tetra Whisper 40i Internal Filter for aquariums is the ultimate in quiet, convenient 3-stage filtration. This submersible filter mounts on the inside of the aquarium, rather than hanging from the outside, making it possible to place the tank flush against a wall and easily hide with tank décor. The air pump (included) provides bubbles that move water through the filter, efficiently filtering and oxygenating your aquarium. The water flows through Ultra-Activated carbon, absorbing odors and discoloration, as well as through the dual-sided mesh of the Bio-Bag Filter, trapping debris and fish waste. Filters up to 170 GPH while oxygenating water. The Tetra Whisper 40i Internal Filter adjusts easily to high or low water levels with a mounting clip. Each unit includes the filter, air pump, 2 feet of airline tubing and one large Tetra Whisper Bio-Bag Filter cartridge (change monthly – replacement small filter cartridges available). For 20-40 gallon tanks. Since 1951, Tetra has developed the world’s most comprehensive body of fish food knowledge, and fishkeeping enthusiasts have looked to the brand for products and solutions that add ease and beauty to their home. Whether you're an experienced hobbyist or just starting out, Tetra has everything you need – from a large variety of quality fish food and innovative equipment to test kits and decor.


Is Discontinued By Manufacturer ‏ : ‎ No


Product Dimensions ‏ : ‎ 5.13 x 5.88 x 10.5 inches; 1.5 Pounds


Item model number ‏ : ‎ 25818


Date First Available ‏ : ‎ July 15, 2004


Manufacturer ‏ : ‎ Tetra


Country of Origin ‏ : ‎ China


Domestic Shipping: Item can be shipped within U.S. International Shipping This item can be shipped to select countries outside of the U.S. Learn More


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, May 22

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • How can something so simple work so well?
Size: Up to 40-Gallons
Review Image by Ronald L. Russell Ronald L. Russell
Review Image by Ronald L. Russell Ronald L. Russell
When you open the box, the Whisper 40i (or it's smaller siblings) don't seem very impressive. It's not much more than a oval plastic bucket, with another bucket (containing a motor and pump) snapped onto the bottom. If you looked at one and thought "this can't possibly work", you would be so wrong. Perhaps they work as well as they do BECAUSE they are so simple, and so have little chance for things to break. The pump sits IN your aquarium water, so it never needs to be primed. You plug it in, and it begins working, filling the upper bucket, where the water flows through the filter pad and spills back into the aquarium. No priming necessary ever, including after a power failure. When the power comes back on, it just starts working again. It's a shame that every hang-on-the back power filter can't make a similar claim, some unfortunately will lose their prime and/or fail to restart, resulting in unhappy fish and sometimes a damaged filter. There are no adjustments for flow, so these only run at one flow rate. Inevitably, some food can get sucked up if you let it run while feeding. I have the filters on a separate power strip, so when I feed my fish, I just use the switch on the power strip to turn the filters off for an hour or so. Easy solution and prevents the filter pads from clogging so quickly. There is no top or lid (unless you buy the model intended for reptiles), so the filter pads just sit there exposed. This means that the water in the filter is fully aerated as it passes through the pads. It also means that no other internal filter is as easy to change pads when they become clogged. The top edge of the pad is above the water line, so you just grab it with two fingers and lift it out. You don't have to disturb the suction cups or hanging bracket at all. You don't have to put your whole arm down into the tank. Maintenance which is easily performed is more likely to be done when needed, so easily changed pads are more likely to be changed when clogged. You have options for how you want to attach the filter. The box includes two suction cups, and a newly designed bracket which hangs over the edge of your tank. I use the bracket, as it's adjustable for height and I don't have to worry about suction cups losing their suction. The filter pads are the Whisper bio-bags, which amount to a thick fluffy poly bag, over a plastic frame, with carbon granules inside. Replacing these is simple, and if purchased in a 12 pack from Amazon, cost about 60 cents per bag. I used Emperor filters for years, and in my experience, these bio-bags work a lot better than the filter cartridges for Marineland products and cost much less to buy. If you rinse them under tap water, which is easily done, the cost is even less. Rinsing the bags doesn't disturb your biological bacteria since they are on a separate part (resembling a hair brush) which remains in the filter when you remove the bags. You do have some flexibility with regard to media options as well. You don't have to use the carbon which is included with the new pads. You can put anything you want inside the bag, and if desired, transfer it to the new bag next time you change them out. You also don't have to use the separate biological "hairbrush", and if you leave it out, you have room to put another media bag in it's place, with ceramic rings, or whatever else you can think of. I have four of these, mounted on two separate tanks, one 55 gallons, the other 75 gallons. All four of them are not quite silent, but very quiet. There is a soft, low hum from the motor windings, a little bit like a transformer humming. At first there was also a faint sound like air trapped somewhere, perhaps cavitation in the pump? But these sounds are hard to hear, and not distracting. And the cavitation sound went away on it's own after a few days. I can hear the soft humming sound if the room is totally quiet and I stand near the tank, but if there is any significant sound from conversation, crunching breakfast cereal, a radio or TV, etc, then they are drowned out. Some of the complaints others have mentioned in their reviews sound a bit like operator error to me. For example, one person said the filter overflowed and sent water over the back of the tank onto the floor. Clearly, the filter was mounted too high....mine are mounted with the top edge 2 inches below the rim of the tank. When the filter pad becomes clogged, it WILL overflow, but into the tank, not out of it. Some describe loud mechanical noises, which sounds to me like a bit of gravel, or perhaps a snail, found it's way into the pump impeller. Yes, this can happen with any filter, regardless of brand, but it's easy to repair. In these filters, the bottom just snaps off, exposing the pump impeller, which is then easily removed for cleaning. And some have complained that the filter "stops working" after some months of service. Again, this is likely due to a need for a cleaning of the impeller and the recess where it sits, where debris or gunk sometimes builds up and prevents it from rotating. On a benefit/cost basis, these filters look really good. They are made of a tough, slightly flexible plastic, so even if you drop one on the floor, it is unlikely to break. Parts for Tetra/Whisper filters are readily available everywhere. And the results are as good as any other filter I've ever used, regardless of cost. The first attached photo shows two mounted in my 75 gallon planted tank, which contains two Nigerian bichers, and two Pictus catfish. The second shows two more in my 55 gallon community tank, with various tetras, cory catfish, and loaches. ... show more
Reviewed in the United States on September 26, 2018 by Ronald L. Russell Ronald L. Russell
    • Great value, super easy to clean.
Size: Up to 40-Gallons
This filter is as simple as can be, and that is not a bad thing. The media is easily removed without having to remove the filter, and so maintenance is a cinch. Being submersible also makes these very quiet, although the larger 20-40 gallon filter does make some noise and can it can also be awkward to place under a glass top tank due to its bulk. I prefer the smaller ones also because they are so silent. I use two 20i filters on each side of my 40 gallon tank rather than the larger 40i. The 40i is also a bit flimsy as the handle can come loose as the snaps that hold it in place can fail, and so a little superglue can be helpful. I still give the 40i 5 stars because despite some faults, it cost just $15 dollars! ... show more
Reviewed in the United States on August 12, 2023 by Gregg H
    • Quiet & Easy-to-Clean
Size: Up to 40-Gallons
Bought this for my turtle tank, which ended up meaning that I had to clean it more often than if it was for a fish tank. Even though I had to replace the cartridges often, it was easy to do so since all you do is lift them up without removing anything else. The filter is fairly quiet, I didn't really hear the filter for the most part. The sound of water pouring back into the tank made more noise than the filter itself, which can be reduced by keeping the top of the filter somewhat near the water line. Another thing that made more noise than the filter itself was my turtles bumping into the filter whenever some food got stuck behind it and they tried reaching it. Another issue some people may have is that the cable may be a little too short. If the tank you place the filter in is too far from an outlet, you may need an extension cord of some sort. ... show more
Reviewed in the United States on July 18, 2023 by Daniel Acevedo
    • Decent for $5!
Size: up to 4-gallons
Review Image by Sam Chap Sam Chap
I bought the 5 gallon filter to go on my 10 gallon betta tank. I must say I was pleasantly surprised it arrived quickly and even though simplistic it is quiet and works fairly well. It comes with two ways of attaching one is a clip that goes over the top edge and the other is a suction cup. Be warned the clip is not wide enough to go over a regular aquarium rims I had to use the suction cup but I imagine if you build something for it to slide into it would work. The 5 gallon definitely is only made for 5 gallon tanks but this one works fine for my 10 gallon because I have aquatic plants in tandem that are filtering the water and only one betta with low bio load. Overall if you're just looking for a cheap filter to get you by and keep the water moving I would recommend. If you need this to agitate the surface to create oxygenation it is not quite powerful enough for that you would need a bubbler added ... show more
Reviewed in the United States on July 27, 2023 by Sam Chap Sam Chap
    • BEST PRODUCT FOR MY FISH TANK
Size: up to 4-gallons
This product was very quiet and very useful for keeping the fish tank clean. I had purchased this because my boyfriend just got us fish and we are new fish parents. I was looking into something that was quiet but would keep the fish tank clean until we cleaned the fish tank every other week. 10/10 highly recommend ... show more
Reviewed in the United States on September 2, 2023 by Dee
    • It was a very good product I have no regrets
Size: Up to 40-Gallons
Review Image by Miakoda Fischer Miakoda Fischer
I wanted to get a good filter for my African clawed frog and this filter instantly started to work it got rid of every little speck of mess that he left in his tank although the suction cups were hard to put on you just have to run them under hot or warm water and they work just fine.
Reviewed in the United States on August 14, 2023 by Miakoda Fischer Miakoda Fischer

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