# Should I get rid of my filter?



## Ags11 (10 Jan 2021)

I have a 30 cm cube tank with a small sponge filter. I clean the filter once a month but it doesn't seem to collect anything. In my old tanks from the early 2000's the filter would get full of sludge in a couple of weeks, but this little filter just feels like sponge and no dirt comes out in the cleaning bucket. Possibly the flow is not enough and the filter is surrounded by thick grass that probably intercepts most dirt.

The airstone built into the sponge filter isn't very good and the bubbles are quite coarse. I am thinking of replacing the entire filter with a good airstone. I suspect that the lush growth in the tank including rampant surface plants would provide enough biological filtration.

The tank is stocked with 5 CPDs and two Nerites. I do 40% water change every week.

Attaching two pictures of the tank - once when it started showing the little filter unit and another showing the current level of plant growth.


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## dw1305 (10 Jan 2021)

Hi all,


Ags11 said:


> I clean the filter once a month but it doesn't seem to collect anything.





Ags11 said:


> I suspect that the lush growth in the tank including rampant surface plants would provide enough biological filtration.


You are probably seeing <"complete oxidation">. I'd keep the sponge filter, but you might be interested in the posts by @Bart Hazes <"Low flow and no........">.

cheers Darrel


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## Zeus. (10 Jan 2021)

A small air stone fitted on the end of the air pipe may help improve performance/flow through the filter/sponge, but does it need as Darrel points out if you follow his link.


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## Ags11 (10 Jan 2021)

Thanks - nice to know my tank is in complete oxidation (I am assuming it is a good thing). I never got plants thriving in my earlier tanks, so that explains the sticky goo in my old filters.
I may look at buying or making a filter with a better airstone.


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## dw1305 (10 Jan 2021)

Hi all, 


Ags11 said:


> I am assuming it is a good thing


I think so.

cheers Darrel


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## Simon Cole (25 Jan 2021)

You want the outlet tube going to the surface to get the maximum amount of draw.


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