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Dosando silica em aquarios

Enviado: 09 Dez 2010, 15:41
por Celso Suguimoto
Esse artigo é bem interessante... embora controverso ainda

Imagem

It has been long held that silica in reef tanks is bad, very, very bad. We avoid beach and play sand like it’s poison because it is believed that silica will cause an undesirable diatom bloom: brown glass, brown gook on rock and substrates, and unhappy reefkeepers. But what if we could control this system and use it to our advantage…say, to increase nutrient export? Let’s take a look at some old data, some new data, and a controversial hypothesis regarding the intentional dosing of silica to our reef aquaria.

Diatoms take many shapes (the photo above, by Dr. Gordon Taylor of the School of Marine and Atmospheric Sciences, my academic “home”, shows a collection of polar diatoms). It is well established in biological oceanography that diatom blooms occur when seasonal upwelling of nitrates combines with longer sunlight and warmer spring waters. These diatoms can exist as benthic coatings, like the brown coating we see in a newly cycling tank, but the bulk of them in the ocean are in the water column. Once the diatom bloom commences, nitrate levels drop precipitously until they can no longer support growth, and the diatoms are either eaten by zooplankton or fall to the bottom of the sea. One thing that is unique to diatoms is that they build shells out of silica, or “tests”, which are symmetrical and some of the most beautiful creatures you will find.

The Old Data: Because we have all learned the dogma that “silica is bad”, silica levels in our tanks are typically way below the level found in reefs (Randy Holmes-Farley, 2003 ). As a result diatom growth is silica-limited, so the diatoms are not performing one of their useful tasks—nitrate removal. The diatoms that do exist in established tanks are not only found as benthic coatings but throughout the water (many commercial phytoplankton products contain diatoms).

The New Data: Dr. Ken Feldman, a chemist at Penn State University, gave a lecture at MACNA XXI concerning skimmer efficiencies and skimmate production and quality. As part of the study he dried down and analyzed the minerals contained in typical skimmate, and largely there were no surprises—carbon, nitrogen, phosphorus. But one thing that struck me at the time was an unexpectedly high concentration of silicon. Because the skimmate was rinsed to eliminate all dissolved minerals, the silicon could only have been part of an organism—and here’s where the hypothesis comes in.

The Hypothesis:

1. Skimmers are particularly good at removing planktonic diatoms, hence the high silicon concentration in skimmate.
2. Diatoms in reef tanks are growth-limited by a lack of silica, but are good nitrate utilizers.
3. We can dose silica to increase the diatom growth rate, the diatoms will utilize the nitrates in the water then get skimmed out, thus giving us a new way to control nutrient export.

Now of course this is merely a hypothesis and will need to be tested to prove its worth, but some anecdotal evidence leads me to believe silica dosing might be beneficial and at least do no harm. Dr. Holmes-Farley dosed silica into his tanks with no ill effect—in fact, he reported that the film that did aggregate on the glass was green and easier to remove than what we usually scrape off. “The Grumpy Old Reefer” reports dosing silica as well, with no ill effects. The added benefits of silica dosing may be interesting as well—sponges also depend on silica, so they may also grow faster. We will have to compare skimmate and nutrient levels from tanks with added silica to control tanks to see if there is a measureable benefit


http://reefbuilders.com/2009/10/30/sili ... nt-export/

O estudo sobre skimmer é esse :

http://www.advancedaquarist.com/2010/2/aafeature

Re: Dosando silica em aquarios

Enviado: 09 Dez 2010, 20:11
por dletieri
Pera lá... Se meu inglês não me trai, diatomáceas, que "comem" nitratos só não se multiplicam mais nos nossos reefs por falta de silicato promovido pelos nossos skimmers???? (nossos? icon_assobiando ops.... seus... rsrsrsrs)

A proposta deste cara é dar silicato pras diatomáceas comerem nitrato e serem arrancadas com nitrato e tudo do aquario.... É isto???

Dá vontade de estudar biologia nestas horas! rs

Interessante, Celso!

Re: Dosando silica em aquarios

Enviado: 09 Dez 2010, 21:02
por Celso Suguimoto
A proposta dele é q diatomaceas seriam excelentes consumidoras de nitrato e sao facilmente exportaveis pelo skimmer. O fator limitante para o crescimento delas é a silica.

O Randy se nao me engano dosa silica no aquario dele...

É uma proposta diferente...

Re: Dosando silica em aquarios

Enviado: 09 Dez 2010, 21:13
por dletieri
Interessante... Antes de construir a casa nova com o aquario novo, vou terminar de equipar este aqui, e vou querer me inteirar destas propóstas... Vai que é algo realmenre 'usável'..

Aposto que o primeiro cara que falou de dosar vodka no aquario deve ter sido visto com olhares estranhos pela maioria dos aquaristas....
Certo que tem umas doideiras, tipo nego que fez um reator de arroz... Mas vai que é uma doideira válida...

Re: Dosando silica em aquarios

Enviado: 09 Dez 2010, 22:56
por Marcio Gielfi
Celso Suguimoto escreveu:
O Randy se nao me engano dosa silica no aquario dele...



Sim, desde 2003 ele faz isso !!!

Dosar silica não é novidade, Randy testou pela primeira vez em 2002, e tem muita gente na RC que dosa silica, outra vantagem é que as diatomáceas consomem o nitrato e fosfato mais rápido que as cianos, logo, voce além de exportar facilmente, ainda evita ciano no aquário ... http://www.advancedaquarist.com/issues/jan2003/feature.htm

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 05:49
por Fernando Leibel
O Basso dosa Silica com a finalidade de manter esponjas, talvez durante esse processo tenha notado os efeitos descritos. Estive em sua casa vendo seu aquario e apesar de dosar silica a agua e transparente e nao se nota diatomaceas em ponto algum.

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 07:32
por Celso Suguimoto
O fato de Randy usar silica e isso ser usado por esponjas está citado no final do artigo

Dr. Holmes-Farley dosed silica into his tanks with no ill effect—in fact, he reported that the film that did aggregate on the glass was green and easier to remove than what we usually scrape off. “The Grumpy Old Reefer” reports dosing silica as well, with no ill effects. The added benefits of silica dosing may be interesting as well—sponges also depend on silica, so they may also grow faster. We will have to compare skimmate and nutrient levels from tanks with added silica to control tanks to see if there is a measureable benefit


A novidade é a exportacao pelo skimmer, esse estudo é recente ainda

6) Silicon analysis

The 4.76% by weight silicon present in the 470 mgs of skimmate suggests that there are 22.4 mgs in total of Si present. If we assume that the Si is contributed by biogenic opal from the skeleta of diatoms, (Brzezinski, 1985; Mortlock, 1989) then the Si is in a hydrated polymer of SiO2 (approx. molecular formula for opal is SiO2•0.4H2O, 42% Si by mass). Therefore, we can approximate the amount of biogenic opal present as 53 mgs (~ 11%).

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 08:05
por jose Jorge
Acho que a colocação da Areia de Praia no Aqua do Basso.......teve esse propósito se não me engano...........comentado por ele já faz um tempo.........

É bem interessante mesmo............ele usa Siporax e Areia de Praia............Nitrato zerado......

Grande Tópico Celso........ icon_joia

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 11:20
por dletieri
Ele dosa cilica usando areia de praia? Eu notei o aparecimento de uma esponja em meu aquario... rsrsr... em menos de quatro meses.... rsrsrsrs.... Parte do meu substrato é de areia.... kkkk

Será????

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 11:34
por Celso Suguimoto
Nao...

I use oolitic aragonite sand (which I bought from Home Depot when they used to sell it as play sand) primarily because I think it looks better.


http://www.reefcentral.com/forums/showt ... ?t=1517322

Aqui ele faz o comentario sobre areia de praia

Is it OK to use silica sand? Probably. Many people do so. I also believe that not all “silica “ sands will be the same for the reasons described above relating to processing of the sand and the nature of the mineral inclusions present. So the fact that many people successfully use some (or many) types of silica sand does not necessarily imply that all people can use any type of “silica” sand without a problem.

In subsequent sections of this article I describe dosing recommendations for adding soluble silica. Is silica sand a good way to go from that perspective? I cannot really answer that. It probably provides some silica to reef tanks, but the amount is completely out of the control of the aquarist. For that reason alone, I believe that it would be a poor choice as the sole source of soluble silica for a reef tank. In a tank without any silica dosing, silica sand may, in fact, be more beneficial to the overall tank, at least from a silica delivery standpoint, than calcium carbonate sand. There are, of course, many other differences that might be the deciding factor on sand choice (color, texture, dissolution, particle size distribution, nutrient and metal binding properties of sands, etc). Many of these factors are more aesthetic than technical, and the technical ones are beyond the scope of this article.


Na realidade hoje eu ainda sou resistente em relacao ao uso de silica em marinhos, entretanto vejo seu uso interessante como auxiliar no combate a cianos por exemplo, do q o uso de antibioticos como vejo alguns fazerem por quererem resultados rápidos. Eu demorei um ano pra acabar com briopsys e derbesias do reef... tentativa e erro... e elas foram sumindo.

Dosar silica para incentivar diatomaceas eu ainda tenho ressalvas... esteticamente compromete e prefiro outras formas para controle de nitrato e fosfato .

The limitation of silica, inhibiting the growth of diatoms that would otherwise take up the limiting nutrients nitrogen and phosphorus, has even been implicated in blooms of cyanobacteria

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 13:25
por Ronaldo Ribeiro
rss,
aqui o problema são as esponjas rosas, agora que vou tirar os lps e vou colocar alguns anjos, provavelmente elas sumirão, espero, virou praga aqui.
tenho que tirar as esponjas manualmente.
abs

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 15:03
por jose Jorge
interessante mesmo.......

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 16:48
por Fernando Leibel
Na verdade o Basso utiliza um produto importado que contem Silica com a finalidade de alimentar esponjas e nío o substrato de areia com essa finalidade

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 20:28
por jose Jorge
Mas teria diferença entre um produto para as Esponjas......e um produto para ser dosado para crecimento de Diatoms.........e consequentemente exportação de nutrientes.......???

Re: Dosando silica em aquarios

Enviado: 10 Dez 2010, 21:44
por Fernando Leibel
Nao.. A Silica esta lá.. só escrevi para deixar claro que ele nao dosa silica usando areia de praia como falado acima

Re: Dosando silica em aquarios

Enviado: 11 Dez 2010, 08:31
por jose Jorge
Desculpa....me enganei..........