I had this idea pop in my head the other day so I tried it.
it might have some promise if it wasn't so ugly. A black sponge might look better, but I use these kind of yellow sponges (cheap dollar store giant car sponges) for sponge filters now and then. Th cell pores are tight but not closed and the sponge is stiff and easy to cut.
Given a few months, it will turn brown with bacteria anyway.
Plus I'm not real fussy of something actually works.
Anyways, I was looking at the overflow from this hang on the back standard filter box, and it occurred to me the nice clean water coming out just passed through a really thickly coated bio filter pad, so if there is anywhere tons of good bacteria is being shed all the time its right there.
I rigged a bunch of boxes, nets, bags, ect ect under the outflow and none really seemed unique and workable.
Then I remembered to keel it simple, a good engineering mantra.
So, ya take the big yellow stiff sponge, gut it and make a box, out of the sponge itself.
Theoretically, in my head the advantages are a last stage water filter, a nice place for bacteria to grow, being subject to a constant fresh flow of water (right out of a heavily laden bio pad).
I made wire clips to hang it snug right under the spillway, and it sticks out of the water about 1/2 inch. Then it occured to me this is cool, since you know by watching it that ALL the water from the filter is going right through the sponge, and not overflowing it. I'm sure in time as the sponge fills with bacterial slime, it will but it IS a sponge, a few squeezes in some clean water and it should be clean enough to contain the water and let it slowly seep out and not overflow the "spongebox".
it's a prototype and its rough but it seems to work just fine, if you can handle the ugly color. The placement doesnt actually take up much room at all, and I suppose if one wanted to it could be made as big or as small as you wanted it to be.
It's a basic idea i thought I'd toss out there.
I dunno if this has ever been done, if so, oh well. LOL
If not, here it is.
I like this idea better than a big old sponge filter block taking up space on the tank floor, which was actually my motivation for making it. Plus it doesn't make that annoying glug glug glug noise all day from the bubbles. Bacteria should colonize in this pretty quickly since the filter boxes bio-fiber pad is well coated and clogged with the stuff.
seems like this is a little backwards. you should have it on the intake as a prefilter, I buy fluval big blue sponges, they are round with a insert in the middle, just cut one of the 2 pak in half, then place ON intake and presto !! there is your filtration + you can have shrimp & fry they wont get sucked up the intake ! and your not cutting off your flow from your filter. In a planted tank, you would not want to cut off your flow, because you need it to strengthen your plants, also more flow more air for the fish . all in all better to place a sponge on the intake for the biomass. Also if you were buying a bottom sponge it would be for the fry , or breeding which makes this sponge on the intake SO much better .
uknow , you maybye could even slide it over where the intake is, then it would be filtering all the water coming threw, and would still be doing what you want it to . just thought about that after looking at your pics once more . I love new ideas, and they always need tweaking, so all in all good job. just move the box over to let the flow free, and the intake would be in the box, and you have made your bio-filter, and a safe haven for fry, shrimp,. etc. ~~~
well as I look I see it probally wouldent be tall enough to still be above the water line, hhmm... yes do some tweaking ....
Sponges on the intake work fine for fry guards, but this sponge box works great for my new project. I wanted a low- or zero-flow tank so I could raise fairy shrimp, but I also wanted a fair amount of filtration since I wanted to maintain a high bioload with blackworms in the substrate, so what I did was add a sponge box to the outflow, and place a drinking glass under the intake, adjusting the water level so that the glass forms the world's smallest sump. The small sump size requires makeup water daily to compensate for evaporation, and the pump has to be primed now since the water level is lower than a HOB filter is really designed for, but it works great.