Live Bacteria

The water has to be able to flow adequately through a filter. If it's too tightly packed, the water flow slows down, reducing the amount of both food (ammonia/nitrite) and oxygen reaching the bacteria.

Did you also know that synthetic sponges come in two types? There are those that soak up water and hold it and those that allow water to run through them. For use in a filter, it has to be the last type. If you want to use cheap sponges rather than expensive aquarium ones, not only do you have to make sure the sponge hasn't been impregnated with some sort of cleaning chemical, you also have to make sure it's the right type.


Fish food will also decay better if it's crumbled up as lots of little pieces have more surface area than one big piece. The bigger the surface area the faster it will decay because the micro-organisms that do the decomposing can get to more of it.
I use the word micro-organism as there will be bacteria, fungi, protozoa etc not just one type.

That's right. Although all the media will house bacteria, some do it better than others. Coarse sponges with big holes are a better biomedium than small fine sponges with small holes, but there's not very much difference. And with their small holes, fine sponges are better at trapping debris.
Though both are the type that lets water flow through. It's sponges like car washing sponges that hold water.

Oodles not Noodles lol.

I re-positioned a couple of my filters, the reason being they were tight up in the corner of the tank and only one side was exposed to the water intake where as the other was tight against the glass.
I know eventually the bacteria will populate that side but I thought by having the water to gain access to both sides it would be more beneficial.