Aquaclear H.O.B. Filter MOD

Aquaclear H.O.B. Filter MOD

The word Aquaclear or "AC" is a word known by almost every Aquarium Hobbiest. Also when it comes to Aquaclear Filters there is another word that is synonymous with these filters. MOD, short for modification. Type these 2 words in google and you will get a ton of different MODS people have done to their Aquaclear filter.

Here is one that I use and really let's begin!

I am not sure if everyone has seen or even heard of a aftermarket filter basket that is made for "AC" filters. They are super expensive and it also has a little bypass. If you haven't seen or heard of this basket this is what it looks like.


At around $50.00 for a AC 70 basket these things are a little expensive.

The way I do my setup is not the same as the basket above but, the way I do my setup, ensures that almost all or very close to all the water that passes through hits some type of media.

What you need is.............

Some foam, make sure that it's longer than the stock grey media basket that comes with every AC filter.

It looks like this......


You need to measure how long the side and bottom of the grey stock media holder, and cut the foam according to its size. It should look something like this.

Image 85.jpg

Image 79.jpg

The one on the left is for the side and the one on the right is for the bottom.
Also you need to decide on how thick you want the sponge. The thicker it is the less room you will have for actual media. I make mines kinda thin as it is to mainly trap larger particles and to house any BB that grows on it. It looks like this.....

Image 81.jpg

Now once you have cut your sponges put back the stock grey media holder into the filter. Now place the cut sponge into the filter.
Note- you see the black lines I made on the top right in the picture. Make sure when you cut the sponge, you cut it all the way to the top. This is to make sure that water is passing through the sponge and not just over it.

NOTE: Make sure that you put the sponge on the side closest to the motor.

Image 88.jpg

Now it all depends on what kind of media you use. In this particular AC I use the cylinder type media, pond matrix, and Biohome Ultimate. I place my media with the hole in the middle facing up. The reason I do this is that so water can freely move through the hole and it also knocks off dead bacteria and letting new bacteria move in its place.

This is a top view of how it looks like.......

Image 86.jpg

I keep on layering on my media until it's almost to the top. Like this......

Also since the media is dry and after hanging it back on the tank, I get some dechlorinated water and I add some Dr.Tim's one and only to the water and then I pour the water and bacteria into the filter. I let it sit there for a couple of minutes so that the biological media can absorb some BB and the BB can maybe settle down onto the media.

Image 93.jpg

It looks like this after I fill it with dechlorinated water and bacteria.

Image 95.jpg

I also use on my filter a pre-filter. This can be made with the same sponge that you used for this MOD.

Also note that I leave a tiny space between the filter and the top of the pre-filter. The chopstick is pointing that out. The reason I do this is because, if the pre-filter gets really dirty water can still freely move through, without putting any strain on the motor.

Image 96.jpg

Finally, I hope that this article can help people improve their AC's and their water parameters.

If you guys/gals have any questions please feel free to ask!

Enjoy and Tank You Very Much!

Tanks and Plants (Brandon)


Tanks and Plants
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How is this going to help you unless you have a grossly overstock tank or severely underpowered filter? Bacteria can only survive if you have a food source. Adding more media for BB does not magically make it grow. If you need this much BB you likely just need a larger filter or move some fish to another tank.
Awesome detail. Definitely trying
Gives me something to think about . That should make it more efficient , will give it a shot
Tanks and Plants
Tanks and Plants
Thank you! This is why I like the Aquaclear Filters. You can adjust it to your needs. I personally like more biological filtration and this way gives me the room to fit all the biological media I can fit. I use this method on all my Aquaclear filters and I haven’t had any problems. You will be able to tell when the sponge is gunked up. The water will be trying to go over the area with the impeller. Because the sponge is all gunked up the water has nowhere to go because it is being blocked. Once that happens it’s time to clean it.

Thanks for your positive review!

Definitely need to try this mod... This tutorial was super helpful and I hope to do this in some way in the future of my freshwater aquarium.
  • Mike
  • 5.00 star(s)
Thanks for taking the time to put this together!
  • shiv234
  • 5.00 star(s)
awesome. I am planning to get one but notices that water usually goes over the top of the filter so i decided not but after seeing this i decided otherwise
  • r15u5
  • 5.00 star(s)
Great step by step
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