Silicate???

Kershaw · Mar 15, 2016

ok so with silicate based sand, what causes it to release silicate into the water. Is it caused by low or high ph or is it another chemical that releases it. Since the other sand buffers the ph by the ph dropping it breaks down the sand raising ph. So I am just wondering what causes the silicate to be released. Thanks.

JimWelsh · Mar 15, 2016

http://www.advancedaquarist.com/2003/1/aafeature1#section-7

redfishbluefish · Mar 15, 2016

HERE's a Randy article that talks about silica.....about half way through he specifically talks about silica sands.

JimWelsh · Mar 15, 2016

Beat ya'!

Kershaw · Mar 15, 2016

Thanks. I tried googling it but I guess I was not asking the right question

JimWelsh · Mar 15, 2016

I used "randy holmes farley silica sand". I find that for aquarium chemistry stuff, just prepending "randy holmes farley" to the simple search term works very, very well.

Randy Holmes-Farley · Mar 15, 2016

Did it answer your question?

IMO, the fastest release of silicate from new sand, especially sand that is not natural beach sand, is the dissolution of silicate minerals that are exposed at the particle surfaces, as opposed to the slower dissolution of silica itself.

Here's a graph of silica solubility in fresh water as a function of pH:

https://www.lubrizol.com/Dispersant...pers/Solutions-Chemistry-Impact-on-Silica.pdf

Kershaw · Mar 15, 2016

Yes it did. I am using beach sand from a beach ca. It is mix of quarts and garnet. The garnet. Randomly I will have small algae out brakes on my sand and glass. And when po4 and no3 are checked it is extremely low or undetectable. So I will run gfo and it goes away. It appears as nothing changes that causes the bloom so I was just wondering how much silicate is actually in my tank.

Randy Holmes-Farley · Mar 15, 2016

Kershaw said:
Yes it did. I am using beach sand from a beach ca. It is mix of quarts and garnet. The garnet. Randomly I will have small algae out brakes on my sand and glass. And when po4 and no3 are checked it is extremely low or undetectable. So I will run gfo and it goes away. It appears as nothing changes that causes the bloom so I was just wondering how much silicate is actually in my tank.

FWIW, diatoms need silicate and are golden brown, but they also need a source of N and P, just like green algae.

Kershaw · Mar 15, 2016

Are there any issues with garnet. Here is a link to where I get sand from that talks about the sand. http://www.sandatlas.org/pfeiffer-beach-sand/

Kershaw · Mar 15, 2016

When this sand was collected, the focus was on purple parts of sand.

brandon429 · Mar 15, 2016

Randy as we have been talking about sand rinses in other threads I had posed the idea that during production, shipping, grain grinding etc the wet pack bagged sands present with a super mega high surface area silt factor (flocculants often included in the bag to remedy) that should be pre rinsed out instead of sinked. literally removed, leaving only heavier sand grains...not floc'd to the bottom.

considering your mention of surface area and dissolution I kept thinking the powder vs the grain sure sounds more presentable silicate to the system, and early invaders who feast on that. Blast rinsing 100% of the dusty silt out of my tank always seemed to factor with zero diatom stages. My theory was that since 99% of reef tank builders feel that rinsing live sand will destroy its bac complement we universally start out tanks with a high fraction of silt and the tank invaders that often show up could have been lessened by starting differently, whats your take on Si being more readily available to the system by not pre-rinsing?

Randy Holmes-Farley · Mar 15, 2016

Kershaw said:
Are there any issues with garnet. Here is a link to where I get sand from that talks about the sand. http://www.sandatlas.org/pfeiffer-beach-sand/

I'm not really sure of the solubility of any of those in normal water relative to silica.

Kershaw · Mar 15, 2016

Ok thank you for your help.

Randy Holmes-Farley · Mar 15, 2016

brandon429 said:
Randy as we have been talking about sand rinses in other threads I had posed the idea that during production, shipping, grain grinding etc the wet pack bagged sands present with a super mega high surface area silt factor (flocculants often included in the bag to remedy) that should be pre rinsed out instead of sinked. literally removed, leaving only heavier sand grains...not floc'd to the bottom.

considering your mention of surface area and dissolution I kept thinking the powder vs the grain sure sounds more presentable silicate to the system, and early invaders who feast on that. Blast rinsing 100% of the dusty silt out of my tank always seemed to factor with zero diatom stages. My theory was that since 99% of reef tank builders feel that rinsing live sand will destroy its bac complement we universally start out tanks with a high fraction of silt and the tank invaders that often show up could have been lessened by starting differently, whats your take on Si being more readily available to the system by not pre-rinsing?

High surface area may well impact the rate of dissolution.

One prominent reef expert once "proved" that silica sand cannot dissolve because our glass tanks are made of it, and they are not dissolving. One factor he forgot is the very much higher surface area of sand vs flat panes of glass (and the second is that one might hardly notice a tiny bit of dissolution from the glass surface).