Filter Media

[raptorrex]

stemming from a recent thread on the subject:

is there any information on the sort of surface area you need, within your filter, to promote best colony health. many manufacturers state so many bio balls/grams of media, for so many gallons, even though some of them can't even supply me with a actual surface area for the product. and how do you actually go about finding the surface area of a bit of efisubstrate, in the first place?

finally. chasing around trying to find information on the subject, i found a few "tests" comparing relative surface areas. but all these reviews gave the information in cubic feet. is cubic feet not a measure of volume, as opposed to area. and how could i convert it to square feet?

 

[smegforbrains]

Measuring by volume is the correct way to do it. Why are you trying to work it out as surface area?

 

[raptorrex]

Measuring by volume is the correct way to do it. Why are you trying to work it out as surface area?

comparing the different kinds of bio media, both proprioty and home made.
how can a volume be the right way to measure surface area? volume would measure the gaps in the media which is considerably bigger than the surface area would be. err i think. lol.

 

[Darkstar]

Volume would be the standard way to do it, but yes imo also, its not an accurate way to estimate the effectiveness of bio media. Surface area would be a more accurate way to do it eg. a cup full of golf balls would have considerably less surface area than an equivalent cup full of sand. Using volume is a handy way to judge the amount you need to fill up your filter but not an accurate measure of how effective it might be.

 

[raptorrex]

Volume would be the standard way to do it, but yes imo also, its not an accurate way to estimate the effectiveness of bio media. Surface area would be a more accurate way to do it eg. a cup full of gold balls would have considerably less surface area than an equivalent cup full of sand. Using volume is a handy way to judge the amount you need to fill up your filter but not an accurate measure of how effective it might be.

indeed. the makers that do give information, measure the area in square feet anyway!
something that caused this research. one manufacture that i contacted for information said, it would not release the information for "commercial reasons"? whilst claiming their product was 20% better than "classical ceramics". so i set about finding the surface area of "classical ceramics". this led to, why is it important anyway? and if its important, just, how much do you actually need?

 

[Darkstar]

This may help...but then it might just make things more complicated also.

http/www.fishyou.com/surfacearea.pdf

 

[raptorrex]

This may help...but then it might just make things more complicated also.

[URL="http/www.fishyou.com/surfacearea.pdf"]http/www.fishyou.com/surfacearea.pdf[/URL]

thanks for that, one i have not seen but it covers things i was, already, considering. part of what i was hoping to find out, was after finding the surface area of media, was how effectivly different media types, utilised it. it seems to me that irregular shapes, or large holes, in the media will just clog up. rendering that section of the media, less effectivley, if not usless. tied in with this is, how are the different media types suited to the different filtration systems we used.

 

[aaronnorth]

many manufacturers state so many bio balls/grams of media, for so many gallons

It is quite hard to do, because it does not take into account the stocking levels. If you stock lightly in a 10g, then put a filter rated for a 100g tank on it, then you will not get bacteria covering the whole surface area as there will not be enough ammonia to feed all of the bacteria, so therefore you cannot calculate how much you will need. Also remember that different fish species produce more poo than others - plecostomus sp for example.

Just a thought

 

[calsonic]

the more surface area the better i always fo above the recomendations then that gives you leway with your stocking and it never hurt to over filter i wopuld of thought it would be virtually imposible to give an acurate surface area on a most ceramic media as they varry so much from piece to piece

 

[raptorrex]

many manufacturers state so many bio balls/grams of media, for so many gallons

It is quite hard to do, because it does not take into account the stocking levels. If you stock lightly in a 10g, then put a filter rated for a 100g tank on it, then you will not get bacteria covering the whole surface area as there will not be enough ammonia to feed all of the bacteria, so therefore you cannot calculate how much you will need. Also remember that different fish species produce more poo than others - plecostomus sp for example.

Just a thought

irrelevant i am afraid. if i were to test the effectiveness of a bio media, i would do it along the lines of a fish less cycle. adding a specific amount of amonia. tank size would only be relevent to the amount of amonia needed to atain the required ppm, and stocking would be, as i say, irrelivant.

the more surface area the better i always fo above the recomendations then that gives you leway with your stocking and it never hurt to over filter i wopuld of thought it would be virtually imposible to give an acurate surface area on a most ceramic media as they varry so much from piece to piece

i see your point, but too much media, may, cause the bacteria to be tooo small an area, reducing the "dwell" time. several manufacturors state "surface area" for their products, so someone can measure it.

 

[OldMan47]

There are at least 2 factors involved in the effectiveness of a particular biomedia. The surface area of the media is the place where the bacteria grow so of course the surface area that will fit in your filter is a factor. That is best expressed in terms of area per unit of volume. Another important factor is that the water with the ammonia or nitrites in it must reach a place on that surface to be converted to the next chemical in the cycle. Even more important is that the bacteria must be able to live on that surface and still receive the nutrients they need in the water flow. In order to do that, the pores in a material can not be so small that water won't flow past the surface when it has a coating of bacteria on it. What that means to me is the outrageous claims by some manufacturers about the micro-porous materials they can achieve through various processes is meaningless. If the pores are too small to see, they are probably too small to establish a bacterial colony and then get water to flow past the surface of that colony. There are also lesser factors in filter media effectiveness such as how well you can fill the filter volume with the media. An example is the plastic pot scrubbers that have a very high surface area per unit volume but unless you have an unusually shaped filter they will leave huge areas for the water to bypass them unless you cut them to fit.
The experiment that boboboy proposes would need to involve measuring the volume that you are filling with media and then would need to measure how much ammonia can be processed, not in terms of ppm but in terms of actual volume of ammonia. Any media will process 5 ppm of ammonia unless the filter is grossly undersized for the tank. What you want to know is if you are using a very marginal filter, which media can keep up with a very overstocked bioload. If I add 20 ml a day of ammonia to a given tank and have a cycled filter of X media, can it keep up? If I change the cycled media to Y, will it still keep up? This tells me whether X or Y media is better as a biological media. This assumes that both media were thoroughly cycled to the same state of readiness, the temperature and other water parameters in both tanks are identical, the filter volumes that I filled were identical, etc.