just how much ben bacteria lives in the substrate?

[fishorama]

I don't believe there is a "one size fits all" answer to this. There are far too many variables that need to be accounted for. The very water itself can be a large determining factor when you try to answer. Next item would be the filtration. The amount of water flow and the amount of contact time with the air all play a role in it. Contact time with the air effects the O2 content which in turn will affect the aerobic bacteria colony. (When I mention filtration, this isn't in reference to mechanical or biological media). I have no bio-media as such in my filters which would place the role of colonization into my substrate (which is PFS).

As far as diatoms go, I find that phosphorus (?) or Phosphate, I don't remember which, has the greatest effect on them and has little to do with substrate. I have used sand as well as gravel without having a diatom bloom so I discount the silica as a sole reason for it.

Gee kinda like what I said except for the phos/phosate for diatoms, didn't realize they were an issue :silly:

 

[Jspigs]

The beneficial bacteria are spread throughout the aerobic portions of the aquarium; glass, substrate, scape, plants and filter. The size of the colony is dependent on the amount of food available... we all know this. Sand has probably the largest ratio of surface area to volume of all the substrates we use. This is why such a small volume of sand in a fluidized bed filter can handle the bioload of a large tank.

With enough surface area exposed to oxygenated water, additional biofiltration isn't necessary.

The fact that your tank didn't experience a cycle can probably be attributed to low stocking density coupled with a larger portion of the biobed living in the filter. When the available food exceeded what the bacteria in the filter could consume, they reproduced to meet the excess. Exact percentage the sand held? Who knows... any number given is pure speculation.

Mark

:iagree:

Agreed.

There is no set amount that lives in the sand and no safe way to measure it. It would depend on filter, maintenance, how often the media is replaced, bio-load, decorations in the tank, type of sand, depth of sand, and probably a few dozen other factors that we don't even know about. Basically for you it could have been 1%, for someone else it could be 50% (or even more) of the bio-filter.

:iagree:

Agree with Mark although you most likley had a ton of good bacteria in the sand, your tank had enough elswhere to make up for the loss. Also, I think the main reason folks have bare bottom is that there is no place for the "poop" and uneaten food to stick to so there are far less nutrients for bacteria and algae to feed on.

:iagree: I am pretty sure that the nitrifying bacteria found in aquaria are capable of doubling their numbers relatively quickly. I forget exactly how fast though.

Chlorine and Monochloramine may not kill BB on contact as one may assume, it always depend on their [conc] and if memory serves, nitrifiers may be more resistant to standard [Cl2], [NH2Cl] than other common pathogenic bacteria. Perhaps due to such reasoning, some may or may not experience problems after drastic changes/disturbances on well established tank. At least one the the reasons.

I agree that chlorine and chloramine do not kill beneficial bacteria on contact, at least not in the concentrations found in most tap water. Another thing to consider is that unless you are changing 100% of the water or close to that amount, the chlorine/chloramine that is in tap water will be diluted by the tank water thus slowing the speed at which the chlorine/chloramine kills the beneficial bacteria (Or even reducing it to a relatively harmless level in some cases, not that I recomend putting chlorinated water in your aquariums without detoxifying the chlorine/chloramine.). This is why people have been able to get away with forgetting to add dechlorinator when doing a water change and only remembering an hour or so later without any form of ammonia or nitrite spike or any ill-effects from the chlorine/chloramine.

Nitrifying bacteria are also a lot hardier than many people think.

I don't believe there is a "one size fits all" answer to this. There are far too many variables that need to be accounted for. The very water itself can be a large determining factor when you try to answer. Next item would be the filtration. The amount of water flow and the amount of contact time with the air all play a role in it. Contact time with the air effects the O2 content which in turn will affect the aerobic bacteria colony. (When I mention filtration, this isn't in reference to mechanical or biological media). I have no bio-media as such in my filters which would place the role of colonization into my substrate (which is PFS).

As far as diatoms go, I find that phosphorus (?) or Phosphate, I don't remember which, has the greatest effect on them and has little to do with substrate. I have used sand as well as gravel without having a diatom bloom so I discount the silica as a sole reason for it.

I agree that there is no real answer to this question since every tank is different. I think that in the OPs' case that she probably did remove a good portion of her nitrifying bacteria when she removed her substrate but the bacteria in other areas (Such as the filters) were able to reproduce and make up for the loss pretty quickly.

Silica sand is also inert so I doubt that was the cause of the diatoms. Perhaps the diatoms on the sand itself may have gotten some silica from the sand but not the diatoms elsewhere in the tank.

I personally do not buy the long term effectiveness of those ceramic or similar high porosity medias because they may very well have a very high surface area but they also clog easily even with rinsing in old tank water or other bacteria safe maintenance methods(or at least that is my understanding). I think that a bio media which is less prone to clogging and easier to clean (such as nylon pot scrubbies, course sponges/foams, bio-balls, etc.) would be a better choice. Also, have you ever seen the manufacturers of such products state how much surface area is needed for certain stocking levels? I am not trying to bash any companies with that statement but rather say that a super large surface area is not always needed.

But back on topic, I think that it varies from tank to tank but generally I would say that for most setups a large amount of nitrifying bacteria reside in the substrate as well as the filter. The exact percentages of nitrifying bacteria in the substrate and filter for most setups will of course vary greatly, for example a tank with a substrate such as gravel or sand and a filter that does not have any bio media and has the mechanical and/or chemical media changed frequently will likely have much more nitrifying bacteria in the substrate than in the filter whereas a tank with a substrate that is either inaccessible or inhospitable to beneficial bacteria and has a filter filled with coarse sponges, pot scrubbies, or the like will have likely a large percentage of nitrifying bacteria in the filter and less in the substrate. You also have to take into account that beneficial bacteria don't read books and as a result we can never be sure if an aquarium with "x" substrate and filter setup will have more bacteria in the filter or substrate.

So the bottom line is we can look at a tank setup and come up with a theory as to where the bacteria are likely to be, but there is definitely not a standard answer and any theories we make could easily be completely wrong especially since every tank is different.

P.S. My fingers are tired after typing this lol.

 

[bluemeate]

sand bed also has much less circulation going through/over it