Whisper® Internal Aquarium Power Filters

Product No. 25816-01


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The Tetra Whisper internal aquarium filter is the ultimate in quiet, convenient 3-stage filtration. The dual-sided mesh of the Bio-Bag® catches debris and fish waste while the activated carbon absorbs odors and discoloration. Biological filtration is provided by the Bio-Scrubber. Bio-Scrubber's anti-clog design provides complete biological filtration with the convenience of less maintenance. Because the Bio-Scrubber has a solid back, water is forced to flow evenly over the bacteria-rich bristles. The filter is submersible. NOTE: The filter now comes with a clip to hold the filter. If suction cups are needed please contact Consumer Services at 1-800-322-1266.
Whisper® Internal Aquarium Power Filters is rated 3.2 out of 5 by 51.
Rated 2 out of 5 by from Not for Aquatic Turtles I bought this due to my big filter was just to much my hatchlings were growing and I still have a month before I get to move them home from college into my 40 gallon tank. I bought this filter so they had more room to swim and they do but the problem is it doesn't have a way to adjust it or extensions for reptiles I can't fill the water too much or they try to escape off the turtle docks... as well as my new dock suctions to the floor but can't cause the water level is to hight to but it's not stable nor does it stay in one place... I wish you made an extender or more than 3 holes so the water height wasn't so high so they had basking space .... so recommend not using this for turtles
Date published: 2016-11-30
Rated 5 out of 5 by from Great product! I bought two 20-40 gallon Tetra filters for my 20 gallon tank that have 4 goldfish. They were working fine until I woke up one morning and saw the water was a little cloudy. I put some clarifier in hoping it would help. The next morning the water was so cloudy I couldn't even see the fish. I took a water sample to Petco and she said it was ammonia and I bought something for that. Before putting it in I decided to do a 25% water change. I noticed instead of vacuuming up debris that I was getting sand! I then put the fish in another tank while I emptied the whole tank to get the sand out - even the filters had sand in them. Then I set it up again and the water has been crystal clear now. I solved the mystery of the sand: apparently one of my cats was standing on the cover at night dipping his dirty paws into the filter where it bubbles seeing the filter doesn't have a cover. I now cover the top of the tank with a piece of cardboard at night so he can't dip his paws in anymore. It is such a relief to see crystal clear water every morning now!
Date published: 2016-11-19
Rated 2 out of 5 by from Missing Bio-filter I have bought a 10i from Walmart and it is missing the bio-filter and grid. I went and check all the boxes in the store are missing the bio-filter! Another Walmart store I went is also missing all the bio-filters. Is it possible to have this part sent to me and find a way to prevent people from taking parts from the box.Thank you
Date published: 2016-10-12
Rated 5 out of 5 by from Good little unit I have owned my Whisper 3i for about 2 years. It has provided constant filtering and kept my 2.5 gal. tank clear. The suction cups now need to be replaced and Tetra is sending them out to me at no extra charge. Great customer service! The tank clip version does not attach properly to the 2.5 gal. tank, but they can be fitted with the suction cups from Tetra. Good little unit.
Date published: 2016-09-15
Rated 1 out of 5 by from Whisper 10i power filter I bought this filter a month ago and had a hard time keeping upright in my 10 gallon tank. I found out from the pet store my filter did not come with the suction cups that would fix it to the back of my aquarium. I had the filter in for 10 days and the aquarium started to cloud up. I have been feeding the fish the same amount of food as I did before the aquarium filter and never had clouding problems. I even bought another biobag filter cartridge and cleaned it first under the tap water as instructed and still have been getting cloudy water within 3to 4 days. I am not very happy with this filter. I only have one large 4 inch goldfish in the tank. I cannot figure out why it will not keep my ten gallon tank clear.
Date published: 2016-09-14
Rated 5 out of 5 by from Still worked great I got one from a garage sale. It was missing a bunch of parts and left unclean in the used aquarium I bought. Probably been sitting dry for years from the looks of it. I cleaned it up, put in a new filter bag and plugged in the power. WOW! The pressure and flow was high and instant. Works great! Now I just need to get the missing parts like one more suction cup or hanger hook.
Date published: 2016-08-31
Rated 5 out of 5 by from Love this product. My fish and I love this product. I followed the instructions. The best part of this is the relaxing sound of water that I fall asleep to. Customers with concerns need to fill their tank and/or change filter.
Date published: 2016-08-28
Rated 5 out of 5 by from used these for years I just purchased a new one to replace one I had for a number of years. I use the whisper filter in my class aquariums. They are easy to set up and are quiet and easy to change the filters. I have 2 medium and 3 large ones (in various aquariums).
Date published: 2016-08-19
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How often should the filter cartridge be changed?

Asked by: JFK332
Thanks for asking JFK332! That depends on whether you have a fish or a turtle tank. For fish, approximately every 3-4 weeks. For turtles, it may be as often as every 1-2 weeks, depending on your feeding and maintenance routines.BREX
Answered by: BREX
Date published: 2016-12-08

How long should two whisper 40i filters on a 37gallon tank last? Does this filter come with a warranty?

Asked by: Captain Morgan
Thank you for your interest in this Tetra product! They come with a two-year manufacturer's warranty against defects. The filter systems typically last 5+ years. They require typical maintenance every month or two of course, to keep them operating for that long. Remove the bottom cover with a Phillips screwdriver, then pop the motor off of the filter body. Remove the bottom cover, pull out the impeller, clean it and swab out the inside of the motor with a q tip. If you tend to have hard water, please use distilled white vinegar. If you need a set of instructions with pictures detailing this, please let us know and we would be happy to email them to you. You can reach us at 1-800-526-0650 or techsupport.tetra-fish@spectrumbrands.com or via the Ask A Question feature on our site.BREX
Answered by: BREX
Date published: 2016-12-01

Can you decrease the flow of the Whisper 10i filter?

Asked by: Amylynd
Thank you for your interest in this Tetra product! Unfortunately, no, it does not have a flow control on it.BREX
Answered by: BREX
Date published: 2016-11-28

I change my EX20 carbon filters regularly but I'm not sure how often the bio-scrubbers should be cleaned. I just changed the filter and the bio scrubber has a white build up on the scrubbers. Should the bio scrubber be cleaned when I change my filter ?

Asked by: Ginger Snap
Thank you for your inquiry! We only recommend cleaning them when they appear pretty clogged. Otherwise, the build up on them actually helps to biologically filter the tank. For cleaning purposes, use water from the aquarium if possible. So for example, after a water change, take the bio scrubber out, and with an old, soft toothbrush, clean it off in the bucket of dirty water. That's all there is to it! Be sure to not use any chlorinated or really hot, really cold water.BREX
Answered by: BREX
Date published: 2016-11-17

i bought a Whisper 2-10 internal power filter not three or four months ago and i was cleaning it and i unplugged it and now it wont turn on what should i do

Asked by: barfbag
Thank you for your question! Remove the motor from the bottom of the filter system, take out the impeller and clean it. You want to remove any debris you find, both on the impeller and in the motor region, and then soak the impeller in distilled white vinegar for 15 minutes. Take a q tip and vinegar and swab out the motor region.BREX
Answered by: BREX
Date published: 2016-11-09

There is a switch on the bottom back of the filter, the instructions don't say if the switch needs to be pushed left or right. Does that matter?

Asked by: Dcap
If you have the micro filter which comes with some of our small kits, there are some lines on that switch. If you push it towards the lines that gradually get smaller, you slow the flow rate down. If you push it towards the lines that gradually get larger, you increase the flow rate, so yes, it matters. Bettas, for example, typically prefer the minimum flow rate.BREX
Answered by: BREX
Date published: 2016-10-17

I just recently bought the 3i and wanted to know the proper way to insert the filter. Does the plastic grid go facing the spout or away from the spout? Thanks

Asked by: RexO
It faces the spillway.BREX
Answered by: BREX
Date published: 2016-10-11

How often should I change the filter?

Asked by: Andre5
Depending on your stocking levels, and maintenance routine, once every 2-4 weeks.BREX
Answered by: BREX
Date published: 2016-10-05
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Whisper Internal Filter Instruction Sheet

Whisper 3i In-Tank Filter Instruction Sheet


Aquarium Size

Cartridge Size


up to 10 gallons



up to 20 gallons



up to 40 gallons