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Unread 01/25/2018, 06:26 PM   #108
Belgian Anthias
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Join Date: Oct 2009
Location: Belgium
Posts: 608
Quote:
Originally Posted by Tripod1404 View Post
I dont get what is the difference between being "skimmed out" and "being carried on the surface of the foam". What is skimmed out is also being carried on the surface of the foam, that his how a foam fractionator function. I dont think it matters that much as long as it ends up in the collection cup.

Skimmed means that a bound is made with an oxygen bubble. It is explained in the previous added link about skimming. It matters as not skim-able compounds accumulate in the system. It is good to know what ends up in the cup and what will not end up in the cup



Also for the 35% of total removed organic matter being bacteria, is that the value with carbon dosing or is the the amount removed in a tank w/o carbon dosing ? Because carbon dosing is known to significantly increase skimmer output. The increase is most likely bacteria or bacteria-based molecules.

Read the article about skimming and open links to the references.


Even than 35% is not a small number. I would actually expect the value to be a lot less. That is like 1.5% of removed organics is nitrogen inside bacteria. And like Bertoni pointed you dont have to remove intact bacteria, bacteria based products can also achieve this. Some bacteria that gets into foam will lyse before they can reach the collection cup, some will die or lyse within the tank and their contents will end up in skimmer. So you wont just have bacteria within the skimate, but the bacterial content. So the actual indirect export can be a lot higher. There would also be output from stuff like bacteria that is being consumed by other organisms (like bacteria ->copepod->fish). In my experience carbon dosing increase copepod populations, which indicate nitrogen in these bacteria can end up in a variety of different members of an aquarium. And from there nitorgen can go to skimmer, like in fish poop form or continue to be recycled among the organisms. These indirect outputs would be something hard to measure, you can potentially dose carbon-14 ethanol or acetic acid and make a radioactive tracing to see how much of it end up in the skimmer, fish and etc. and extrapolate a rough number for nitrogen (like 1 nitrogen atom for every 6 carbon atoms, which is the average ratio within a cell ). But I dont think anybody is doing or done this.




It means that minimum 65% may be recycled, A problem is that most of this 65% contain compounds that will not be skimmed, also not on a next passage true the skimmer, they accumulate. Activated carbon seems a lot more effective for removing DOC. But this has nothing to do with carbon dosing.

Yes, it becomes part of the food chain!

When I want to add something to a live support system I like to know what I am doing.
I do not like the fact that the carrying capacity support of system may become dependable of the dosing .
What is a good reason to add carbohydrates not knowing what may happen by doing so?
How difficult exporting nitrate may become?


I am not disagreeing that autotrophic nitrification is a lot more effective, but here I assume you are talking about sulfur based chemo-autotrophic assimilation. This is something I am very wary about the long term safety. I personally know someone whose tank nearly crashed to a sudden burst of H2S production. For an autotrophic assimilation nitrate process, using macro-algae or even mangroves is a lot safer.

by using SPC, I am talking about autotrophic nitrification and simultanious autotrophic and heterotrphic denitrification, not of autotrophic assimilation. Autotropic assimilation would not change much as growth is very slow compared to heterotrophs.

I have not suggested to use sulphur denitrators but SPC. Some sulphur denitrators are used and managed as they where heterotropic denitrators, which must be kept annoxic. These things are not safe for the short term safety when badly managed.

Sulphur denitrators are used with success in a lot of public and home aquaria since a few decades now. The oldest installations are used in the MAAO These systems, build following the guidelines of M Longouet, are NOT kept annoxic after start up. http://www.baharini.eu/baharini/doku...ess:bades:maao
Sulphur reactors must not be kept anoxic, Everything about BADES:
http://www.baharini.eu/baharini/doku...n:badess:start

Sulphur can be used as base for growing a nitrifiying biofilm.


Is regular carbon dosing completely safe,of course no. It can cause bacteria blooms and suffocate the tank. It depletes some elements that we do not regularly test for (most notably potassium). But I have never heard anybody experiencing a sudden ammonia burst during carbon dosing. Considering carbon dosing is probably being done by thousands of people, lack of empirical evidence suggest it is not as likely as you suggest it to be.


Ammonia may build up when dosing is stopped, not while dosing, Nitrification does not take place when most ammonia is removed from the water column by dosing. Most bacteria present in the water column will deplete ammonium before using nitrate; this was explained at the opening of this threat. and the reason why this discussion was started. Reinstalling the nitrification capacity takes time.


When using SPC I know what I am doing; I know the side effects and how I can avoid them. Nitrogen is exported. No capacity shift.

And all in all there is one major problem. What you describe can only reduce nitrate but not phosphate. So you need an additional mechanisms to control phosphate, likely GFO or aluminum based absorbents. When you add these do the mix, it generally make the system phosphate limited and would effectively reduce the efficiency of nitrogen reduction. On the other hand carbon dosing can reduce both.



SPC will export nitrogen, not recycle it, without influencing the carrying capacity balance


When using GFO one can control the phosphate removal rate if it is used in a reactor. As phosphate is a limiting factor for the survival off all live, I rather would have some control over the removal rate. How depletion of phosphate is prevented using carbodosing as it is based on the nitrate level? One can do it biologically by activating phoshate accummulating organismn (PHO) http://www.baharini.eu/baharini/doku...:filtratie:bpr
.
Why make it difficult?


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