Questions about sponge filters

Hello,

I have a 2.5 gallon planted RCS tank. The HOB filter that came with the tank was much too strong; it would blow the shrimps around and kick up a bunch of dirt. (I used organic gardening soil and gravel.)

After hearing about sponge filters I decided to go with that route. I bought a cylindrical Fluval sponge (not sure exactly what it was designed for; it has a circular opening at one end) and inserted an airstone and airline tubing in one end. I wedged it in a corner of the tank, and when I turn the air pump on, bubbles come out through the sponge.

It's adding surface agitation, which has eliminated the oil slick that had occurred on the surface, and it doesn't kick up crud like the other filter did. However, after reading a few threads, I'm afraid I may have misunderstood how to construct them. The posters showed wedging rigid tubing into the sponge, and inserting the air stone and airline tubing in through the rigid tubing. You stand the sponge up on its end, and when the bubbles rise through the rigid tubing, it draws water in through the sponge.

With my current set-up, air passes through the sponge, but water doesn't. I had originally thought that the purpose was to provide a surface for the bacteria to live on, but it sounds like if the water passes through the sponge, it's actually supposed to filter particulate to some extent.

The posters in the thread mentioned that the set-up I used will work, but I'm concerned that it isn't helping as much as I would have hoped. If you have experience with sponge filters, what do you think? Since it's all nice and situated, should I not mess with it? Or is it so ineffective that I should change it to the correct set-up?

Thanks for any info you can provide!

 

If air is passing through the sponge, water is as well. Can you get a picture of the sponge filter?

My RCS love my sponge filters! always grazing on them. I think sponge filters are great for shrimp

 

I did my best to get a few views without actually removing the filter. I'm sure it would let loose a bunch of gunk if I did.

Here's the sponge I used:

The sponge is the black thing with the bubbles coming out (obviously). I also tried (with little success) to draw the set-up in Paint. It's very difficult to draw using a laptop! Hopefully it gets the idea across.

 

Ok, I see what you did there. The act of the air bubbles going through the sponge moves water through it. It should be sufficient for RCS. I'll get a pick of one of my sponge filters so you can see how I make them. GO SPONGE FILTER POWER!

Edit: This is what mine looks like. I have a cap at the bottom then holes drilled where the sponges are. I've got a rigid airline that goes to the bottom. The air going up sucks water in.

 

Interesting, that's much more elaborate than mine. If it's good enough for now I'll leave it; maybe next time I decide to re-scape the tank I'll play with it. Thanks for your help!

 

Nice drawing by the way. lol

 

Thanks! ;D I don't have one of those pad-things you can draw on, and I don't have a mouse so it was sort of difficult. I did my best.

 

So, which of the two drawings are correct? Air bubbles should not be coming out through the sponge. The air/water mix should rise up the tube, drawing water through the sponge.

 

They are both correct. KinezumI does not have a tube. Her application of a sponge filter is correct for the bioload she is filtering.