florida joe
Well-Known Member
Originally Posted by Rockman
http:///forum/post/2631291
Joe I have read a lot of your post and replies and i think your a very intelligent man who knows what he's talking about and I respect your opinions But to answer your last question - In a given volume of sand, the usable bacterial surface area rises rapidly as the average particle size decreases. For example, a cubical particle 1 mm on a side has 6 square mm of surface area, while the surface area on a particle that is one eighth (or 0.125) mm on a side is a total of 0.09375 square mm. However, in the volume of 1 cubic mm, there would be 512 of the smaller particles, for a total area of 48 square mm, eight times what is found on the larger cube.
The total sediment surface area in even a small tank is impressive, indeed. In a 45 gallon reef tank, the sand bed averages about 4 inches deep, by 12 inches wide, by 36 inches long, for a total of one cubic ft of sediment. I won't bore you with the calculations, but if the average particle size is one eighth mm, and that is a good average size to have, the total sand surface area is about 14,828 square feet or just slightly over 1/3 of an acre. A LOT of bacteria can live with that amount of space!
It seems you are using each individual grain of sand for your calculations. Just going on that I have to ask you do you believe that the smaller sand will pack together more tightly then the CC and if so the areas touching now reduce the total area for nitrifying bacteria to form on? Your tightly packed sand now becomes almost a solid (the reason sand sifting animals are added is to break up and add aeration to the sand. Again we are talking about a real life situation in our tanks. This packing effect is not as great in CC leaving a greater total surface area for nitrification to accrue. To further pack the sand any live rock we put in our tank adds to this effect, again in the CC this packing under the rock is not as great.
http:///forum/post/2631291
Joe I have read a lot of your post and replies and i think your a very intelligent man who knows what he's talking about and I respect your opinions But to answer your last question - In a given volume of sand, the usable bacterial surface area rises rapidly as the average particle size decreases. For example, a cubical particle 1 mm on a side has 6 square mm of surface area, while the surface area on a particle that is one eighth (or 0.125) mm on a side is a total of 0.09375 square mm. However, in the volume of 1 cubic mm, there would be 512 of the smaller particles, for a total area of 48 square mm, eight times what is found on the larger cube.
The total sediment surface area in even a small tank is impressive, indeed. In a 45 gallon reef tank, the sand bed averages about 4 inches deep, by 12 inches wide, by 36 inches long, for a total of one cubic ft of sediment. I won't bore you with the calculations, but if the average particle size is one eighth mm, and that is a good average size to have, the total sand surface area is about 14,828 square feet or just slightly over 1/3 of an acre. A LOT of bacteria can live with that amount of space!
It seems you are using each individual grain of sand for your calculations. Just going on that I have to ask you do you believe that the smaller sand will pack together more tightly then the CC and if so the areas touching now reduce the total area for nitrifying bacteria to form on? Your tightly packed sand now becomes almost a solid (the reason sand sifting animals are added is to break up and add aeration to the sand. Again we are talking about a real life situation in our tanks. This packing effect is not as great in CC leaving a greater total surface area for nitrification to accrue. To further pack the sand any live rock we put in our tank adds to this effect, again in the CC this packing under the rock is not as great.
