A
Anonymous
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that and I want a place where bacteria can colonate without being disturbed by the goby and the critters in the bed have a place to properly do their job with out being eaten
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A sand bed in the refugium is perfect. However, for DSB, bigger is better. If I were you I would also add a sand bed in the tank, but that is just me. I ma not at all convince that my sand bed will cause the decline of my tank in the near or far future.
Minh
Minh
Actually properly set up DSB are used to make a place for anarobotic bacteria. In other words bacteria that need a devoid area of o2 to live. O2 is what would cause the crash of the bacteria in the sand bed.
Not a chance. The denitrifying bacteria that consume NO3 are facultative anaerobes. That means they can live and function normally in either aerobic or anaerobic conditions. They do not perform denitrification only deep within the sandbed. They perform dentrification generally when O2 levels reach 1-1.4 mg/L. This can happen at very shallow depths.
Therefore, if you allowed O2 to reach them, these bacteria would quickly deplete the O2 via aerobic respiration, faster than diffusion could resupply it (this is why even in shallow areas/live rock, anaerobic conditions exist), necessitating switching over to anaerobic respiration and breaking down nitrate.
Not a chance. The denitrifying bacteria that consume NO3 are facultative anaerobes. That means they can live and function normally in either aerobic or anaerobic conditions. They do not perform denitrification only deep within the sandbed. They perform dentrification generally when O2 levels reach 1-1.4 mg/L. This can happen at very shallow depths.
Therefore, if you allowed O2 to reach them, these bacteria would quickly deplete the O2 via aerobic respiration, faster than diffusion could resupply it (this is why even in shallow areas/live rock, anaerobic conditions exist), necessitating switching over to anaerobic respiration and breaking down nitrate.
This is a qoute from R. Shimek "In a very real sense, the biological filter depends upon bacterial growth. The breakdown of nitrogen compounds to nitrogen gas is done by bacteria growing in the areas of lowered oxygen concentration in the deeper parts of the sediments. "
Reef Aquarium Vol. 1
"Nitrate is denitrified by facultative anaerobic bacteria that live in anaerobic zones within the aquarium. These occupy the cores of live rock and the bottom substrate. Their proximity to aerobic layers means that nitrate, produced by nirification there, is immediately available to these facultative anaerobes that convert nitrate into nitrogen gas and nitrous oxide."
Facultative=that they may live in the preence of 02 or in its absence. Anaerobic means without 02. When these bacteria occur in the core of live rocks, where there is no free 02 they optain 02 from Nirtate, and reverse the process of nitrification, generating nirtous oxide and ntrogen gas.
So they only preform denitrification when the obtain their 02 from the nitrate not when they live in the presence of free 02. When free 02 is available they just preform nitrification.
So basically nitrate is only converted in 02 devoid areas.
Reef Aquarium Vol. 1
"Nitrate is denitrified by facultative anaerobic bacteria that live in anaerobic zones within the aquarium. These occupy the cores of live rock and the bottom substrate. Their proximity to aerobic layers means that nitrate, produced by nirification there, is immediately available to these facultative anaerobes that convert nitrate into nitrogen gas and nitrous oxide."
Facultative=that they may live in the preence of 02 or in its absence. Anaerobic means without 02. When these bacteria occur in the core of live rocks, where there is no free 02 they optain 02 from Nirtate, and reverse the process of nitrification, generating nirtous oxide and ntrogen gas.
So they only preform denitrification when the obtain their 02 from the nitrate not when they live in the presence of free 02. When free 02 is available they just preform nitrification.
So basically nitrate is only converted in 02 devoid areas.
Minh Nguyen":8j48tb9u said:A sand bed in the refugium is perfect. However, for DSB, bigger is better. If I were you I would also add a sand bed in the tank, but that is just me. I ma not at all convince that my sand bed will cause the decline of my tank in the near or far future.
Minh
This I realize. But when I set up this tank I had no real knowledge of how a bio filter works and set it up looking good rather than running as good as it could have. Please dont get em wrong for my first time I think I did a decent job. The refugium is small because I have limited cabinet space with my sump being there. I am planning to use argonite and a few macros like caulerpa and maidens hair algae for the refuge I already have halimeda in the main which my tang and sandsifter pick at periodically
Good luck with your tank. I think it would be fine. DSB is really efficient at handling nitrates. You will need to find other methods to export phos. Algae/biomass harvest from the tank is excelent way to harvest phos and possible other nutrients from the tank.
Minh
Minh
Sorry to be so blunt in my description, not that in this case this makes a huge difference. I think everyone get the idea!
Galleon, In any case I think we both agree that DSB dont just crash. I also think we both agree that there needs to be anaerobic conditions for the bacteria to complete denitrification. So we really arnt disagreing, after all the simple definition as given in the glossory of TRA vol1 says "Anaerobic- without oxygen." To me this doesnt seem incorrect, the difference is just a minor technicality! I dont think I am spewing any misinformation.
Galleon, In any case I think we both agree that DSB dont just crash. I also think we both agree that there needs to be anaerobic conditions for the bacteria to complete denitrification. So we really arnt disagreing, after all the simple definition as given in the glossory of TRA vol1 says "Anaerobic- without oxygen." To me this doesnt seem incorrect, the difference is just a minor technicality! I dont think I am spewing any misinformation.
For me, I love my DSB. I can keep very delicate corals like Goniopora and grow SPS very quickly. I add a huge amount of Ca to my tank to support my coral growth and my corals are growing out of the tank. My fish are all doing well and breeding the tank. My Banggai cardinal even grew up and mature in my overflow box without me feeding it.
DSB is very efficient at handling Nitrogenous waste. In keeping Marine tanks, I never have undetectable nitrates without a DSB, and never have detectable Nitrates with a DSB. It also provides lots of live food for my tank animals. I got a deep, deep sand bed that is about 6 inch in my sump and average about 10 inch in my tank. The surface area is 34X96 in the tank and 18X48 in the sump. I did seed it very well from many tanks and about 20 gallons of deed mud from the Corpus Christi bay.
I do know the limitation of the sand bed and deal with it accordingly. I change water 25% every 2-3 months (120 gallons). I have three 65 g Rubber maids to mix the water. I have another RO system in my garage to get the RO water needed. I grow lots of algae, mangroves, and sea grasses in my sump. I light my sump with two 250 W MH and harvest the macro algae very regular. I know that what going to the tank got to come out in order to balance the tank. I got a large skimmer for my tank also. The way I think about it, I got to take the same amount of Biomass out of the system as I out into it or very close to it.
My DSB work well for me. If I have to change the DSB out every 20 years, then I will. I don't see evidence that my DSB is causing problem for my tank. I know that my coral are doing great and will keep my DSB until my experiences tell me otherwise.
The important point here is that our tank, as a close system needs to have balance. We cannot add thing into it forever without removing it and expect it to stay in balance. One need to know that the DSB does not export phosphorous well and we as aquarium keeper need to deal with it. I keep my deep sand bed, not because I think it will last forever, unless I have method to remove the phosphorous from the tank. I keep it because I can have much higher biomass density in my tank with it and thus can keep delicate, hard to keep animals.
In living organisms Nitrogen, Phosphorous, and Potassium are there of the most important elements beside Carbon, Hydrogen and Oxygen. Of these phosphorous is the only one that we cannot get rid of automatically in a aquarium with DSB. One just has to have other method of export the phosphorous from the tank. As I export phosphorous from my tank by various mean, I also get rid of the micronutrient like trace element and keep them from get to toxic level in my tank. I also do not intentionally add these trace elements (Iodine, Strontium, trace element soup etc.) in to my tank.
There have been many DSB bashing lately. IMO, that DSB is a very successful method of keeping aquarium. But it is not a magical way to keep your aquarium in balance. It just helps me to keep my animal thriving. It keeps the conditions of my tank much close to nature. That is why I use DSB in my aquarium.
Minh
DSB is very efficient at handling Nitrogenous waste. In keeping Marine tanks, I never have undetectable nitrates without a DSB, and never have detectable Nitrates with a DSB. It also provides lots of live food for my tank animals. I got a deep, deep sand bed that is about 6 inch in my sump and average about 10 inch in my tank. The surface area is 34X96 in the tank and 18X48 in the sump. I did seed it very well from many tanks and about 20 gallons of deed mud from the Corpus Christi bay.
I do know the limitation of the sand bed and deal with it accordingly. I change water 25% every 2-3 months (120 gallons). I have three 65 g Rubber maids to mix the water. I have another RO system in my garage to get the RO water needed. I grow lots of algae, mangroves, and sea grasses in my sump. I light my sump with two 250 W MH and harvest the macro algae very regular. I know that what going to the tank got to come out in order to balance the tank. I got a large skimmer for my tank also. The way I think about it, I got to take the same amount of Biomass out of the system as I out into it or very close to it.
My DSB work well for me. If I have to change the DSB out every 20 years, then I will. I don't see evidence that my DSB is causing problem for my tank. I know that my coral are doing great and will keep my DSB until my experiences tell me otherwise.
The important point here is that our tank, as a close system needs to have balance. We cannot add thing into it forever without removing it and expect it to stay in balance. One need to know that the DSB does not export phosphorous well and we as aquarium keeper need to deal with it. I keep my deep sand bed, not because I think it will last forever, unless I have method to remove the phosphorous from the tank. I keep it because I can have much higher biomass density in my tank with it and thus can keep delicate, hard to keep animals.
In living organisms Nitrogen, Phosphorous, and Potassium are there of the most important elements beside Carbon, Hydrogen and Oxygen. Of these phosphorous is the only one that we cannot get rid of automatically in a aquarium with DSB. One just has to have other method of export the phosphorous from the tank. As I export phosphorous from my tank by various mean, I also get rid of the micronutrient like trace element and keep them from get to toxic level in my tank. I also do not intentionally add these trace elements (Iodine, Strontium, trace element soup etc.) in to my tank.
There have been many DSB bashing lately. IMO, that DSB is a very successful method of keeping aquarium. But it is not a magical way to keep your aquarium in balance. It just helps me to keep my animal thriving. It keeps the conditions of my tank much close to nature. That is why I use DSB in my aquarium.
Minh
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