# How do I know if a Sponge Filter works?



## xxabc (Feb 1, 2010)

As the title says. 

How do I know if my sponge filter is working ? I've just made a DIY one. 

it's in my 5 gallon, however it's divided so it's in a 2.5gallon section. 

The pump is from a tetra filter I no longer used. It's set for 3 gallons. However, I've been told that with the amount of power (?) it's under, it should be fine for a 5 gallon? 

I also bought a 10-30 gallon sponge for it. 

The pipe is very high. About half an inch from the top. I'm planning to lower it, and I will if you guys recommend I do so. If you do recommend I lower it, why? and how much lower? 

It's currently not running under an airstone. It's straight from the air-tube. They ran out at the store, but I tried to do it without it anyways. How necessary is the airstone? And what will be the difference? Thank you~


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## iamntbatman (Jan 3, 2008)

I think you should get an airstone just for better flow. Does your divider allow water to flow through it? If not then the filter's not doing much for the water on the other side of the divider. I don't think you need to lower the pipe. As long as it's below the surface of the water the filter should work fine. There's really no way to tell if it's working (as with any filter, really) other than by checking your water parameters. Sponge filters are nothing more than a big ol' area for bacteria to colonize so if it's working properly you should have zero ammonia and nitrites. On a more basic level, if there are bubbles moving up through the middle of the filter, then water is moving through the sponge so it's doing what it does.


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## xxabc (Feb 1, 2010)

Alright then, I will. The bubbles are pretty _big_ so there's huge surface agitation. 

There's already a HOB filter on the other side, which is why I added a sponge filter on this side for betta filtering. 

Thank you  I tried to do before-hand "experiments" with it, but couldn't find out what I could properly use, so I just plopped it in there.


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## rsn48 (Nov 26, 2009)

Get water testing kit - API is one of the best - and test your water for ammonia, nitrites and nitrates, then you'll know - only way.


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## TankMAster (Oct 16, 2009)

Cut the pipe so that it's under the surface of the water. Thats all that is needed really. If the sponge gets dirty then you know that it is working. Similarly to other filters. If you see the muck on it, it's working!


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