# How to insert an air stone into a sponge filter



## Shadowsun (Jul 15, 2013)

After reading how using an air stone in a sponge filter will make it quieter, I bought one in hopes of making my own sponge filter make less noise. I've run into a problem, however; I can't figure out where to put the air stone in. The rising tube is too small to fit the air stone, and in the inside of the sponge filter there is a plastic tube in the middle that prevents the air stone from fitting. Because the air from the pump goes through this tube to the bottom of the filter I'm hesitant to cut it out. Is there anyway to put an air stone in this type of sponge filter?


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## kittenfish (Dec 1, 2013)

These have a very small diameter and may fit better: http://www.kensfish.com/aquarium-supplies/air-supplies/lees-discard-a-stone-slim-6pack.html


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## Hallyx (Jun 11, 2011)

I think I know what you're getting at, Shadow. Is your filter like the Jardin on Amazon? 

You may not be able to fit an airstone in there without removing the insides and running the airline all the way to the bottom with the airstone on the end. You will need to figure a way to keep the airline down there.

Let me know what kind of filter it is and I may be able to think something up.

The other alternative is to fit a piece of filter foam on the outlet of the riser tube.


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## Shadowsun (Jul 15, 2013)

kittenfish said:


> These have a very small diameter and may fit better: http://www.kensfish.com/aquarium-supplies/air-supplies/lees-discard-a-stone-slim-6pack.html


I don't think we have this type locally, and I'd rather not order online if I can help it.



Hallyx said:


> I think I know what you're getting at, Shadow. Is your filter like the Jardin on Amazon?
> 
> You may not be able to fit an airstone in there without removing the insides and running the airline all the way to the bottom with the airstone on the end. You will need to figure a way to keep the airline down there.
> 
> ...


Yes, if I remember correctly it's this filter. I can take a picture of the insides if it would help.

When I was messing around with the filter yesterday, I noticed that if I took out just the middle part and connected the air stone to the top part of the plastic, the part the rising tube and airline tube connect to, bubbles would come out of the top. Is this kind of what you're talking about?


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## Hallyx (Jun 11, 2011)

That's the one I thought you had. I've seen pictures of the inside. It looks like it would be difficult to fit an airstone.

I can't seem to visualize what you've done. But, if air is coming out of the airstone and rising up the riser tube, you have it working.

Can you post a picture of your modification. I'd like to pass it along. Being able to use an airstone in a sponge filter has definite advantages.


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## Tree (Sep 29, 2013)

I bought some very thin air stones that I might try out for my sponge filters but will it affect my good bacteria in the filters? I just wanna make sure my filter will still work with the air stone in them. 

as you know *Hallyx*, I have this filter. XD http://www.amazon.com/Jardin-Aquari...id=1388289506&sr=1-67&keywords=sponge+filters


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## Hallyx (Jun 11, 2011)

I don't know what's down inside those CAF10 filters. What does the airline attach to down there? Maybe you can just put an airstone on the end of your airline and stick it down in there. As long as the bubbles are rising up the riser tube, it's working. Theoretically, the deeper into the filter you can get it, the better it should work. But in practice, it doesn't make much difference.

I can't imagine how it would affect your bacteria.


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## Tree (Sep 29, 2013)

thanks =) I will test it out later. I took a gander at what was in there and it looks like there was more plastic parts hidden inside. I will have to take a picture of it when I have more time. I did try to take it all apart The riser tube sunk down into the rocks along with the air stone. LOL


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## Shadowsun (Jul 15, 2013)

I finally got around to doing the modifications. In the first picture you can see an idea of what the sponge filter looks like on the inside. The original middle part has been removed and set to the right. Part 1 on the top has been connected to the air stone, which has been loosely set on top of part 2 and the weighted base.

Because Part 2 is no longer connected to part 1, I removed part 2 from the weighted base and used string to connect part 1 and 2 together with the air stone and sponge in between them. You can see a closer look at the two parts and the holes in them in the second picture.

On a side note if anyone else is trying to copy this, because the air stone was slightly too tall to fit comfortably where the middle part was I had to cut part of the spout(blue part) of the air stone. Be careful not to cut it too far down to make sure it'll still fit in part 1. I also had to invert part 2 because a part of it was sticking out into the area the air stone needed to occupy. Part 2 isn't as firmly attached to the weighted base as it was, but it's enough to keep it down as long as it isn't being pushed around roughly.

Right now the sponge filter is producing smaller bubbles that are coming out through the riser tube like it's supposed to, so everything appears to be working well. I haven't seen any bubbles escape out the bottom of the filter or side of part 1. The third picture is what it looks like now.


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