Stupid question for everyone.

As I understand it, all substrate is basically some form of biomedia. It can collect beneficial bacteria and colonize it. Gravel, sand etc...

As I also understand it, substrate has a limited surface area, and thus biomedia for filters was created to have surface area sufficient for large colonies of bacteria.

So....

Why doesn't anyone ever use biomedia as substrate or a supplemental substrate? Appearance? Cost? Some other X factor I am not thinking of?

Cheers,

Joshua

Personally, I don't think I would like the look... Not only that but the expense would be much higher...

From what I have been told, not that much BB lives in the substrate anyway... Good Question tho!

for the looks ,i guess.
my filtermedia would look stupid if i used it instead of my gravel.

hey joshua... as cris have said once and i quote: i hope i said it correctly necromancer...

but to give my idea on it... can you imagine what will happen if your o tried to tear up your media????? further,running water that comes in contact with bb consummate the nitrite and ammonia, thus making the water in good condition... same is true the oxygenation when water runs through the filter media. since substrate just created limited space space for bb, media in the filter compensate the needs...

I thought circulation/water movement over the media would come into contact.

I totally understand. The question crossed my mind when I looked at the SeaChem Matrix. It actually just looks like large gravel. Special gravel obviously.

I don't want to do it, I was just curious. All biomedia in sump: CHECK

Thanks for all the feedback.

I tend to agree that it is because there is inadequate water movement over substrate to allow the establishment of significant beneficial bacteria.

Perhaps a better question would be why don't we use substrate material (sand or gravel) in our filters? My hunch is that would probably work, to a degree, but substrate material probably lacks sufficient surface area to promote the establishment of significant BB.

Of course, I don't have a clue.

water movement on top surface of the substrate...yes... but limited water
in contact with bb... but in filter... though not as large as substrate,
all water passing is in contact with bb.. that is also the reason why there
is an ideal flow rate to make filtration effective...

fast movement is less effective than a normal pacing of flow that gives
enough time to process...

If we didnt use filters, we would need very large tanks for very few fish (like you get in a natural lake).

So we put filters on the tank and create a flow of water through it to give the bacteria enough oxygen to live on. You put a substrate in to make you tank look nice. The media we put in filters doesnt have to look nice but it does need plenty of surface area for the bacteria to live on. The media we buy has lots of surface area for the volume so we can have more bacteria living on it.