# Using sponge in canister filter for media?



## Daximus (Oct 19, 2011)

Silly question, I searched but couldn't come up with anything regarding the use of a sponge in place of bio balls. I was ordering some ceramic rings this evening to put into my canister filter. I was also going to get some bio balls...but then I've started thinking.

Ceramic rings make a lot of sense to me, but bio balls do not. I've heard of people using everything from Legos to pot scrubbers in place of bio balls. I had neither available, but I did have a great big sponge. I cut it up into roughly 1 inch triangles.

My question is does anyone see a problem with this? Is there something special about bio balls that I'm missing?


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## astrosag (Sep 3, 2010)

I don't see a problem with it but at the same time, you're probably not going to see an noticeable advantage from using a bio sponge in place of bio balls. As far as the function of the filter (thinking of my Eheim 2215), I don't see any issue there. At the same time, that's a whole lot of sponge to compensate for my Eheim's bio balls.


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## Daximus (Oct 19, 2011)

astrosag said:


> I don't see a problem with it but at the same time, you're probably not going to see an noticeable advantage from using a bio sponge in place of bio balls. As far as the function of the filter (thinking of my Eheim 2215), I don't see any issue there. At the same time, that's a whole lot of sponge to compensate for my Eheim's bio balls.


I'm not looking for an advantage per se, other than saving a little cash, lol. Bio balls are basically just in place for sheer surface area yes? I'm running an Aquatop CF-500 (works great, love it) that has 4 media baskets. I've got filter in the bottom, then my sponges, then about 20 bio balls, then ceramic rings. 

I just wonder why I've never heard of anyone putting sponge bits in a canister.


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## Seattle_Aquarist (Jun 15, 2008)

Hi Daximus,

If you are referring to a normal sponge like you would use for cleaning it probably will not work. Natural sponges are "closed cell" and water will not easily flow through them. In additional, true sponges will break down over time and decompose.

The "sponges" used for aquarium filters are actually a man made "open cell, reticulated" foam with typically 20-30 ppi (pores per inch). This pore size seems to allow a good compromise between sufficient surface area for bio-film growth and adequate water to flow through the filter.


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## Daximus (Oct 19, 2011)

Seattle_Aquarist said:


> Hi Daximus,
> 
> If you are referring to a normal sponge like you would use for cleaning it probably will not work. Natural sponges are "closed cell" and water will not easily flow through them. In additional, true sponges will break down over time and decompose.
> 
> The "sponges" used for aquarium filters are actually a man made "open cell, reticulated" foam with typically 20-30 ppi (pores per inch). This pore size seems to allow a good compromise between sufficient surface area for bio-film growth and adequate water to flow through the filter.


Ahhh, thank you kind sir. That makes total sense, I was assuming all sponges were equal and simply looking at it from a surface area standpoint. 

If you have a moment...ceramic rings vs. bio balls? Do they serve the same purpose more or less? Why do people run both if yes?


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## DogFish (Jul 16, 2011)

Daximus - There's a guy on the sooner Swap page selling Foam. I like 10PPI, great flow rate, more open area. I use it in all my HOBs. I toss all the stuff they come with and just use a huge block of Foam.


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## Seattle_Aquarist (Jun 15, 2008)

Hi Daximus,

Actually I don't think it really makes much of a difference; they both serve the same purpose - to provide a surface for bio-film growth with minimal impact on the flow through the filter. I find that, depending upon the design, bio-balls may provide more mechanical filtration than ceramic rings and have more surface for bio-film growth.

If you are looking for an inexpensive media for your canister filters, why not augment your sponges/bio-balls with polyester fill material? I use it in my tray type canister filters. Typically my first (and sometime second) trays are the foam pad which I follow with poly-fill packed loosely in the third tray and bio-balls in the last tray.

I use this poly-fil which I pick up locally at craft, sewing, or fabric stores for about $5.


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## DogFish (Jul 16, 2011)

Check that Poly fill label.

Sewsalot posted about some of that poly having a fire retardant chemical on it. She "sews" and uses the stuff. That was on the equipment forum.


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## Seattle_Aquarist (Jun 15, 2008)

Dogfish is correct, no flame retardants!


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## GeToChKn (Apr 15, 2011)

I have used plastic pot scrubbers and bbq lava rock for bio material before. You can also use any type of sponge. I've used dish sponges, car wash sponges, whatever I can find at the dollar store. The whole key if you are using sponges is put them in an order of coarsest to finest for the flow of your filter, so smaller and smaller particles make it through to the last set of filters. If you're looking for general bio material, plastic pot scrubbers work for it though. Unravel one of those things, you have like 50yards of plastic in one of them, lots of bio space.


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## Daximus (Oct 19, 2011)

Thanks for all the replies fellas, and ladies! Really helps out. I think by reading your answers I may have answered my own question.

Again, what I did was cut up a bunch of 1 inch triangles of sponge...so I'm not "forcing" the water to pass through them like cut to fit sponge filter. 

Still, the key is to provide the most surface area possible, *while reducing flow as little as possible*. That's where to sponge has it's downside to a bio ball. After taking apart my can it becomes fairly obvious that my sponges have strategically arranged themselves to slow my flow. No big deal, it's still moving plenty of water...but I'm willing to bet the same amount of bio balls wouldn't hamper the gph as much. 

Cool ideas with the polyfill and the pot scrubbers. If I brave going to town tomorrow (black friday) I'll grab some and play around!

Thankyou everyone! Love this forum and it's willingness to answer the silliest question, lol. roud:


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## wendyjo (Feb 20, 2009)

Some "regular use" sponges have an anti mildew agent in them, so watch out for that. 

You can get a big bag of aquarium polyfill at Petsmart/Petco for pretty cheap. I bought a bag years ago and still have some left. I use it in my canister, in my small internal filters for my betta tanks, and I even use some as a pillow for my air pump to sit on to muffle the vibration noise. 

My canister filter has a mix of polyfill, coarse and polishing sponges (the ones made for my particular filter) and ceramic rings. I also had some crushed coral in there for a long time but it dissolved after about 4 years and I haven't replaced it since I don't have any snails now other than pests.


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## astrosag (Sep 3, 2010)

When I was responding to your forum, I was assuming you were going to using aquarium-grade sponge/foam. 

I sort of skimmed your post and didn't realize that your canister filter didn't come with the filter media (is it used?). Bio-balls are more expensive but you won't need to replace them any time soon - I sort of seem them as a one-time cost. The sponge however will probably require more cleaning/replacement - I would think. Surface area isn't really that important - the lesser of the two choices has more than enough for your aquarium anyways so I would think any gain is negligible at best.

But it can/does work. GL.


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## Jaguar (Oct 13, 2011)

I think the more fine pored sponges and such you have in your filter, the more potential there is for flow reduction, and the more cleaning/maintenance required. Sponges will eventually get blocked with gunk, so you'll have to disassemble and clean an entire filter's worth of sponges routinely, whereas things like Bio Balls, Eheim Substrat, etc. do not need washed. Depending on the type of foam/sponge they do break down and get yucky over time, so you will be replacing them occasionally on top of that. Just my 2 cents though.


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## DogFish (Jul 16, 2011)

I ran those ceramic macaronis in my reef tank and they do need to be rinsed too. Just not as often.

Good quality Open Cell is made as a filter application vs. the assorted $1 store sponges with may be treated with fungicides or mold inhibitors.


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## wendyjo (Feb 20, 2009)

While sponges do get clogged more easily than ceramic or other "hard" media, they also do more for mechanical filtration, and polish the water better than hard media does. This isn't as much of an issue if you have rooted plants that will use the fish waste. I have alot of ferns and anubias that are attached to decor rather than rooted in the substrate, so I like to have a good bit of mechanical filtration in my tanks. The beauty of a canister filter is that you can personalize it to your specific needs.


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