Replacement Fish Filter for Less Then 15 Cents Each




I got tired of paying 3 bucks a filter for my whisper 5-15 fish filter for my sons goldfish and the filters are becoming harder to find in the area I live in so I decided to make my own for what I later figured to be less then 15 cents a filter.  Im sure this same methode could be used on other like filters/pumps that use this same style filter as well, you will just have to adjust size and fit.

Step 1: Make a Frame

The replacement filters I have been buying didn't have any internal support.  Some of them do and some of them don't.  The last one I had did not so I had to come up with some sort of internal frame for the new filter.  I found that a light switch cover to fit perfectly. 

Step 2: Cutting Frame

Now some light switch covers are made from a hard plastic and you wont be able to cut them with a razor knife without cracking.  The one I had in the garage was made of some sort of soft vinyl and I found I could cut it very easy with a razor knife.  I cut it so there was about 1/8-1/4 inch of plastic left all the way around the edge.  You might be able to buy a one of those square light switch covers that already have a large square hole cut them in or maybe even use a plug cover and break out or cut out the center piece.  Whatever you use make sure it will allow for the most water flow for best filtering.

Step 3: Test Fit

Test fit in the pump housing.

Step 4: Cutting Filter Material

You have to get some polyester fill batting.  I got this 6 foot by 3 foot roll (actually its about 9 inches wider then 3 foot) at Hobby Lobby for $6.99.  I figured I can make something like 255 filters out of this.  There are different thickness of this stuff.  I bought the 1/4 inch thick stuff.  I doesnt look to dense and seemed about what the old filters where made of. Cut  a piece of the batting so that it folds around the filter like in the picture.  I cut mine about 1/8-1/4 inch larger then the filter frame.  This will allow some space to glue the thing together.

Step 5: Glue It Together

Then glue it together with hot glue.  Glue 2 of the 3 sides.  I left one of the ends open for the next step.

Step 6: Test Fit

Test fit the plastic frame. 

Step 7: Fill

I used Zeolite to fill the inside of this filter. Zeolite absorbs the dangerous ammonia that fish and food waste create.   You could use activated carbon or a mix of both.  I happen to have zeolite from our turtle tank filter so I used this. I used about 2 table spoons full inside the filter.  Thats just a guess based on how much carbon was in the old filter.  You could add more if you had larger fish or more fish in your tank.

Step 8: Seal and Install

Seal the last side with hot glue after filling then install in the pump.  Including the zeolite each filter only costs me about 14 cents to make and about 5 mins worth of work.  When this gets dirty just cut off the poly fill, dispose of the zeolite and make another filter using the plastic frame.



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    11 Discussions

    This Is gonna Be Awesome!

    Can you tell us the dimensions of you filter? It might be the same as mine! Also, could the hot glue/poly fill fibers affect the water safety?

    3 replies

    Hot glue is great but if you have concerns you can use silicone. They even make aquarium silicone.

    The poly fill for sure doesnt, I have never had any problem with the hot glue. The fish is about 3 times the size he was in the pict now. I have a larger filter but still use the poly fill/hot glue on homemade filters.


    1 year ago

    ¡¡Fantástico!! Thank you very much. This is gold for DIY people. Very well explained, and very well illustrated with photos. Thanks for sharing ;)


    3 years ago

    Love it when folks find a way around spending so much money on this hobby when they truly don't just by using some good-ole common sense :)


    6 years ago on Step 8

    You could try those freezer containers,cut two pieces to match,cut your your batting so it can be folded,add your charcoal,fold,put between the two plastic pieces,and use coated paper clips to hold it all together.Just a thought that I may try myself to save some money.


    8 years ago on Introduction

    I like the idea of the polyfil. I've had the same problem finding the little filters. I pulled out the frame from a used one and cleaned it up, then made a little sack for it from old tights. I use activated charcoal in mine. I think I will add a slice of polyfil as well to catch the finer bits of gook.

    Nice and very clever! Thanks.


    8 years ago on Step 8

    Great idea. I have a 55gal and a 10gal tank, so I go through filters three at a time. I am considering doing this, but am concerned there could be some ill effects from the hot glue. Have the fish stayed pretty healthy?

    1 reply

    Reply 8 years ago on Step 8

    Fish is fat and Happy...I dont think the glue as anything in it that will dissolve...dont know for sure but I have not had any problems with it...