# Question about CO2 and sponge filters.



## Cypher (Apr 15, 2006)

Hey folks, 

Been thinking bout adding some sort of CO2 setup (probably start with DIY) to help with plant growth in one of my tanks. The thing is I also run a sponge filter with an air pump on it. So I was wondering how this would affect the levels of CO2 in the water.

Thanks in advanced.


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## Darkblade48 (Jan 28, 2008)

The air bubbles generated will cause higher surface turbulence, causing your CO2 to off gas faster than normal.

You can compensate by injecting CO2 at an increased rate, but you will obviously go through it faster.


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## bambi (Nov 11, 2010)

Cypher said:


> Hey folks,
> 
> Been thinking bout adding some sort of CO2 setup (probably start with DIY) to help with plant growth in one of my tanks. The thing is I also run a sponge filter with an air pump on it. So I was wondering how this would affect the levels of CO2 in the water.
> 
> Thanks in advanced.


go with CO2 cylinders, worth the price.


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## waj8 (Jun 30, 2010)

Sponge filters are not for CO2 injected tanks. It doesn't take much turbulence to gas off the CO2 and a sponge filter is just way too much.


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## Cypher (Apr 15, 2006)

How bout a sponge filter with a powerhead attached instead?


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## Darkblade48 (Jan 28, 2008)

Cypher said:


> How bout a sponge filter with a powerhead attached instead?


A much better option!


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## waj8 (Jun 30, 2010)

That works. All my tanks used to be like that. Not so good to look at though. Planted tanks do better with a lot of water flow. A 10x turnover without much surface disturbance is very nice. You can put a couple of powerheads with sponges in your tank but they take up a lot of space. For a show tank, it won't look so good, but it is functional.


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## Cypher (Apr 15, 2006)

Thanks for the replies guys. I've a standard circular hydor type sponge filter, what type /brand /model of powerhead would you suggest? Thanks.


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## BillD (Jun 5, 2006)

The size of the powerhead will be determined by the size of the filter. Too much flow and the filter will plug more quickly and you may not notice it. If I were using a powerhead on a sponge filter I would schedule regular cleanings, perhaps weekly, until I determined how often the sponge needed to be cleaned. That is actually good practice even with air driven sponges, as they work better when clean.


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