Put Ceramic Media Directly In Water?

[luckyd]

Hi there. We have four tanks, and only one has a compartment designed to put a bag of ceramic filter media. For the other tanks, our LFS suggested that we can just put a mesh bag filled with the ceremic rings directly into the tank water. Is this good advice? How much good (or harm) would it do? And how frequently would we need to change out some of the rings? Thanks for any advice you can give.

 

[ian]

the media needs to be in place of fast flow, because thats where you get the build up of good bacteria. It'll be no good just dropped in the tank.

 

[Monty-2010]

If your going to put it direct into the water try to get it in front of the output of the filters that way you'll get the water flowing through the rings

 

[hamfist]

the media needs to be in place of fast flow, because thats where you get the build up of good bacteria. It'll be no good just dropped in the tank.

What you say is generally accepted "internet wisdom". However, I'm not sure there is much evidence to actually back it up.
Undergravel filters actually work rather well, with a non-porous filter medium too, and they generally have really quite slow flow through the gravel.

I suspect that a bag of porous ceramic media (NOT just non-porous ceramic rings/tubes) might have quite a good effect, biologically, in an aquarium which had struggling filtration.
If possible, I'd try and site it in an area of reasonable flow. I guess it would be a balance between where it was in reasonable flow, but still looked OK, as it's not going to be the most aesthetically pleasing ornament in the tank.

 

[Corleone]

Undergravel filters have low flow, but over a much larger surface area than power filters. They don't grow the noticeable brown mats of bacteria that power filters do, either - they have smaller colonies over a much lager area.

What ianho said is a bit simplified, but it's still essentially correct. Out in the tank, they'll come in contact with what water passes by, which isn't much even in a high flow tank. In the filter, ALL the water comes through many times a day, meaning that bacteria living in there come in contact with vastly more ammonia than ones in the tank, even though the concentration is the same. So you get thick globs of the stuff growing in the filter, but not out in the tank.

 

[Bignose]

It isn't so much amount of flow that determines where the bacteria grow, but availability of food. This is why bacteria grow in a HOB filter, because the pump brings food to the bacteria. This is why bacteria grow in undergravel filters, the air bubbles dragging water up in the riser causes flow through the gravel bed, and hence food to go through the gravel bed.

If food is in a high-flow area, then bacteria will grow there (the can affix themselves to surfaces with a very strong bond relative to their size if they need to.), or if the food is in low-flow, they will grow there.

Now, regarding the first post. The reason ceramic disks are put into a filter is simply to give the bacteria that will grow in there more surface area in which to grow. And ceramics will be completely inert in the tank. Other than that, there is nothing sacrosanct about ceramics at all.

In any tank, the bacteria will grow. Now, things like the filters with sponges or ceramic disks or the like help create conditions nicer for the bacteria to grow, but bacteria will grow with or without them. Unless there is a filter to put the disks in, they aren't needed. Most filters come with a sponge or some floss to provide nice conditions for the bacteria to grow on -- if your new tanks have those in the filters, that should be good enough.