[mikeh]

I want to make a simple sponge filter to toss into one of my tanks so that it is ready to go (that is, already colonized with nitrifying bacteria) when I need to isolate a fish. I have a commercial one, but it is so tall that there’s very little clearance when I put it in a 2.5 gallon, I’m not crazy about it, etc., etc. the basic design seems really simple, I just am not sure what to look for in a sponge. Can anybody tell me what to look for or give me a specific source? It seems like the kind of thing where you might be able to use something that was not marketed for it, but is perfect for the purpose.
EDIT: I guess one of my concerns, if using something not made for the aquarium is to be sure I’m not using something with toxins.

 

[Aaronious]

you can literally use any sponge. I think if you're going to use just one you will want one that is at least a little course, or larger wholes. I am assuming this will go in an filter at some point. If the holes are too small, or the pores are too small it will clog faster. so the cheaper the better at the dollar store is what I generally do.

 

[mikeh]

you can literally use any sponge.

...the cheaper the better at the dollar store is what I generally do.

Thanks for the coarse suggestion. Is there a way to tell if the dollar store sponges contain any toxins? Safe for washing cars or dishes might not be the same as safe for fish.

 

[Aaronious]

Thanks for the coarse suggestion. Is there a way to tell if the dollar store sponges contain any toxins? Safe for washing cars or dishes might not be the same as safe for fish.

pretty sure it's just if they are like fragrances or not. There maybe a few types that are not so good but usually they are the "higher end" sponges. so all dollar store should be fine.

 

[AVN]

Look for coarse sponge filter with 30-40 ppi. Any other sponge won't be as good.

Search for "manten filter sponge media"

 

[Leeatl]

Check out Swiss Tropicals

 

[sm1ke]

pretty sure it's just if they are like fragrances or not. There maybe a few types that are not so good but usually they are the "higher end" sponges. so all dollar store should be fine.

You also need to make sure they don't have anti-mold/anti-mildew characteristics. Personally I'd check out the auto parts store for a car washing sponge. Usually those are clean, and they're big/thick enough to drill/cut a hole through. Only concern might be density.