Small plastic corner bubble filter

[Mike L]

Curious why you want these?

[apistofrank]

He raises guppies and the group he belongs to
On FB recommends the use of these filters
to lessen the chances of fry getting sucked in

[charlie]

He raises guppies and the group he belongs to
On FB recommends the use of these filters
to lessen the chances of fry getting sucked in

Is there an advantage of box filters over the popular sponge filters breeders use?

[apistofrank]

I might be missing something here but I don't
see any value unless the depleted charcoal acts
like media to let beneficial bacteria grow on it
I like sponge filters

[Herstead]

You don't have to use carbon in it you can use any media for bacteria growth or clarifying the water.

Basically if you want to use high area ceramic balls or something for higher bacteria load or something like purigen for toxin removal you can inside it. If you added foam or floss it pretty much acts just like a sponge filter as far as I know. Also because they generally use fine air stones the bubbles are smaller and more suitable for smaller fry. 

This is just what I was lead to believe though I don't have extensive use of either we have used both.

- Jonathan

[CC-Slider]

I raise guppies and platy's too and I have two small HOB's and a sponge filter in my 30g tank. All I did was get some coarse sponge filter and cut a slit into them and shoved them over the intake of my two HOB's and at the moment I have more little fry's than my tank can handle. I had to cycle my 25 Gallon and transfer half my fry into it as ammonia was starting to show up on my water test, because of the fry explosion. So if you already have a HOB just place a sponge over the intake. It will not only prevent fry from being sucked up it will also super charge your HOB filter by adding a extra place for bacteria to grow.

[Black_Rose]

Fluval edge style pre-filter sponges also work great over the HOB intakes.

I use them on all my tanks with HOBs.
I got some generic ones on Amazon as they use coarser foam than the Fluval ones.

[Mike L]

Contrary to what many will have you believe most bb is in your substrate and on your decorations and not in the filter.
As far as mechanical vs bio media. All mechanical filtration is also bio media. Matten filters. come to mind. My fry grow out tank runs with an ATI sponge filter with a power head only. The fish do fine