zman1
Active Member
I am not a Chemist
and to paraphrase articles (in the links) that some do a good job in layman's terms and others that have a higher understanding of Chemistry - ie CEs. Just the fact I am using carbon, I think it is a standard understanding, it can pull trace elements out. I am doing water changes weekly and can't keep NO3 down where I want it. Some can keep a level of 0 for NO3, I have never been able. I have gotten close before, but never zero. It is also my understanding that NO2 is removed before it can change to NO3 as well. Only time will tell if this is a success or failure.
I am willing to take advice from a Chemist or a hobbyist with experience as to success or more importantly failure of this approach - If you know what I mean... The last time Sarwiz100 shows being on the board was on 1-31-07, I would love to hear what he has seen thus far.
Here is information copied directly from one of the links. by J. Charles Delbeek, M.Sc.
The system uses small beads of elemental sulfur placed in a contact chamber. Tank water is introduced at the bottom of the chamber at a very slow rate and exits out the top. As the water moves slowly upward, oxygen is removed by bacteria, making the chamber more anaerobic the further up the water rises. At this point, the bacteria will use nitrate in the absence of oxygen so that by the time the water exits from the top of the chamber, most of the nitrate has been removed. The chemical reaction that takes place releases excess hydrogen ions, which makes the water acidic.
Nitrogen gas is also produced, and this leaves the water at the top of the chamber (one reason why a reverse-flow design is favored). It is believed that carbon dioxide is also produced in this process, further acidifying the water. To counter the acidity, the effluent from the reactor should pass through another column of crushed coral in which the acidic water will dissolve the coral gravel, raising the pH and generating calcium ions.
Another by-product of sulfur-based denitrification is sulfate. Passing the water through calcareous gravel precipitates this sulfate and prevents it from entering the aquarium. The sulfur beads can last a very long time, but the chamber of coral gravel will quickly turn to sediment and should be replenished on a regular basis. The use of a fluidized bed design for both the sulfur and the coral gravel reactors should help to reduce the build-up of sediments.
This depends on how low such filters can bring the nitrate. Most reef aquariums still have nitrate levels that are a magnitude greater than those found in nature. If these filters can bring down aquarium levels to natural reef levels, they may well be worth the effort to use. On fish-only systems, these filters can easily help bring down nitrates to much lower levels. In addition, with the increase in the numbers of fish and the amount of food being added to reef tanks, a sulfur denitrator may be a necessary tool to remove excess nitrate. Finally, if aquarists want to keep many of the more delicate nonphotosynthetic corals, such as Dendronephthya, which require frequent feedings, these filters would again help keep nitrates under control.
Some of you may be wondering what all the fuss is about, since denitrification filters have been around for over 10 years. The difference is that those filters rely on heterotrophic bacteria to reduce nitrate to nitrogen gas. This means that you need to feed the bacteria a carbon source, usually methanol or ethanol, in a controlled manner, and adjust the amount in response to changes in nitrate levels. Too much alcohol, and you get hydrogen sulfide production. Too little, and you have nitrite and nitrate released back to the aquarium. These filters also produce a large amount of bacterial slime that needs to be removed on a regular basis.
The genius of the sulfur-based denitrators is that they do not need to be constantly adjusted, you don't need to feed them (other than to add some new sulfur maybe once a year or less), and they can also be used in conjunction with a calcium reactor to add calcium and alkalinity to the aquarium. Put simply, they are much easier to use with much less risk than alcohol-based reactors.
I am willing to take advice from a Chemist or a hobbyist with experience as to success or more importantly failure of this approach - If you know what I mean... The last time Sarwiz100 shows being on the board was on 1-31-07, I would love to hear what he has seen thus far.
Here is information copied directly from one of the links. by J. Charles Delbeek, M.Sc.
The system uses small beads of elemental sulfur placed in a contact chamber. Tank water is introduced at the bottom of the chamber at a very slow rate and exits out the top. As the water moves slowly upward, oxygen is removed by bacteria, making the chamber more anaerobic the further up the water rises. At this point, the bacteria will use nitrate in the absence of oxygen so that by the time the water exits from the top of the chamber, most of the nitrate has been removed. The chemical reaction that takes place releases excess hydrogen ions, which makes the water acidic.
Nitrogen gas is also produced, and this leaves the water at the top of the chamber (one reason why a reverse-flow design is favored). It is believed that carbon dioxide is also produced in this process, further acidifying the water. To counter the acidity, the effluent from the reactor should pass through another column of crushed coral in which the acidic water will dissolve the coral gravel, raising the pH and generating calcium ions.
Another by-product of sulfur-based denitrification is sulfate. Passing the water through calcareous gravel precipitates this sulfate and prevents it from entering the aquarium. The sulfur beads can last a very long time, but the chamber of coral gravel will quickly turn to sediment and should be replenished on a regular basis. The use of a fluidized bed design for both the sulfur and the coral gravel reactors should help to reduce the build-up of sediments.
This depends on how low such filters can bring the nitrate. Most reef aquariums still have nitrate levels that are a magnitude greater than those found in nature. If these filters can bring down aquarium levels to natural reef levels, they may well be worth the effort to use. On fish-only systems, these filters can easily help bring down nitrates to much lower levels. In addition, with the increase in the numbers of fish and the amount of food being added to reef tanks, a sulfur denitrator may be a necessary tool to remove excess nitrate. Finally, if aquarists want to keep many of the more delicate nonphotosynthetic corals, such as Dendronephthya, which require frequent feedings, these filters would again help keep nitrates under control.
Some of you may be wondering what all the fuss is about, since denitrification filters have been around for over 10 years. The difference is that those filters rely on heterotrophic bacteria to reduce nitrate to nitrogen gas. This means that you need to feed the bacteria a carbon source, usually methanol or ethanol, in a controlled manner, and adjust the amount in response to changes in nitrate levels. Too much alcohol, and you get hydrogen sulfide production. Too little, and you have nitrite and nitrate released back to the aquarium. These filters also produce a large amount of bacterial slime that needs to be removed on a regular basis.
The genius of the sulfur-based denitrators is that they do not need to be constantly adjusted, you don't need to feed them (other than to add some new sulfur maybe once a year or less), and they can also be used in conjunction with a calcium reactor to add calcium and alkalinity to the aquarium. Put simply, they are much easier to use with much less risk than alcohol-based reactors.
