why southdown why not silica?

[Anonymous]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote

I'm skeptical.

I'm not. I've seen it/worked with it. There is a photo of Dr. Jaubert's original patent-based system from the Musee in Nice in Sprung & Delbeek's first The Reef Aquarium book. It, and many similar systems to further proof of the systems efficiency originally in France, were run closed, without water changes. Its common myth that all his systems were always run partially open.

 

[Hammer]

Like mentioned, filter sand is brown in color. I added this to the bottom for a deeper sand bed. And because the sand I moved over was already 'live'. I didn't want to smoother and kill too much life.
I understand that the lower levels would benifit the most from the aragonite, but 6" of it would just cost too much.
And as far as a DSB, it is working wonderfully so far. But time will tell on that.

 

[olgakurt]

I beleive that article is often misquoted or the interpretation in err. It refers to pure silica not "silica based sand".

I used natural silica (FL) sand in my tank for 10 years prior to moving. I would not pay an arm and a leg for Ca based sand.

That said, I do not believe that Silica-based natural or play sands are chemically inert. "Silica based" sands in most part are not comparable to aquarium glass, pure silica (SiO2) is.

Natural and silica based play sands are composed of a significant fraction of feldspar minerals (1 to 50% is common). Dissolved silicate (not silica) is produced by the weathering/dissolution of feldspar minerals.

Pure silica (SiO2) sand is almost never found except in glass and masonary uses where processed sand is required.

I have done some research on blooms in open and estuarine waters when I was working as a Marine Scientist and many triggers have been proposed. Dissolved silicate is but one of the proposed triggers. Some research indicates that the ratio of nutrients (including Silica) may be more important. There are many ways which the ratio of nutrients may be upset in a tank.

If you are using tap water, you are probably getting most silica through this source. However, one should not be fooled that natural silica sands will not contribute silicate. IMO, most should based on their composition.

[ August 06, 2001: Message edited by: olgakurt ]

[ August 06, 2001: Message edited by: olgakurt ]

 

[Grandczar]

olgakurt...
Very well put!
Im curious, this I address to anyone...
I use to do masonary work with silica specially when folks wanted very white grout lines. The sand I would get was from the brickyard/supply yard. It comes in all sorts of grain size sorta like sandpaper.
But this stuff is very white. I notice most of the silica users here report it being brown in color? If glass is "pure" and you can see threw it? (remember its polished)
Then wouldn't the sand be very white to clear?(unpolished) I know when I've used my diamond tip bit w/ my dremel to make holes in glass. The dust it creates is very white.

 

[StrikeThree]

I have both Quickrete Play sand (The Brown "silica" stuff) and Southdown in my tank. I had only the Quickrete in there for about 3 months and I had no problem. I put in the southdown on top because it looks better.

I thought that the play sand that everyone refers to as "Silica" was actually just land based sand, usually limestone, granite and whatever. It contains silica, among other things, but is certainly not 100% silica. You can usually pick out the silica grains because they are very shiny and reflective as compared to the other grains. Maybe Im wrong, but in watching this Southdown vs Quikrete thing play out over the past 2 years, I have seen it go from "dont use land based sands as they contain silica" to calling those same sands "silica sand". Anyway, just my 2 cents, but there are many who use land sand very successfully.

Brian

 

[gargoyle]

I use the quickcrete playsand found in home depot, could not find southdown. I had a small bout with diatom alge when my tank first came out of the cycle, but since then nothing, if anything I would like to use southdown on my next tank because I like the white look of that sand. My sand looks like a very light tan.

 

[Enkidu]

I found a local dealer that carries white silica sand. The sales rep said they carry both 30 and 70 grit sand. Which should I get? And once I get it, how should I wash it?

 

[Grandczar]

Randy Holmes-Farley:

Couldn't agree more... with the exception being...

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR> Maybe silica sand causes blooms in some tanks, maybe in no tanks, maybe only when the sand is new, I don't know the answer.

<HR></BLOCKQUOTE>

By no means am I an expert. However with that said... I have reached an understanding that it takes more than silicates to grow diatoms. Therefore it can not be solely responsible for diatom blooms. It may make a reef with high nutrient levels more prone to a diatom bloom. Even so why do we single out silicates. Like you said some folks even add it on purpose for sponges, diatoms, etc... Diatoms are great food for snails & corals.

Dont get me wrong though. If you take any un pure source an add it to your tank without taking any precautions. Regardless of what it is it may do undersireable things.

So im left with only one reason to not use silica sand. My only objection now seems to be that this stuff is used for sand blasting.
They use it for this purpose for a reason. The individual grains are not round in shape. Instead they are jagged. Im still unsure as to its long term use and keeping your sand critters happy.

My whole purpose to the link and my post. Was to generate some thought on some things we assume to be fact that may not be... All the hobbies I have been involved in. There are always companys selling overpriced stuff you can most likely find a very inexpensive alternative to. But, Joe Blow is scared that it may not work cause everyone else buys it from the overpriced company.

BTW! Thankyou all for the great responses!

 

[polar1]

Has any one ever used sand from the beach? I just relocated to S. Miami and key Largo is only 25 min. away. I am presently cycling my 125 and thought this would be a cheap option for a 100% LSB.
Would the sand right off the beach(say in 3' of water) be the same as sand in close proximity to a reef?
If this is advisable, should I take any precautions to screen out any unwanted critters?

 

[randy holmes-farley]

Grandczar:

Rob (that author of the article that you link to) and I have thrashed this out on this board before since I don't accept his arguments in that paper. IMO, the justifications for the idea that SiO2 sand is OK are flawed.

It may be true that silica sand is fine for reef tanks, but don't be mislead by that article.

FWIW, I add soluble silica to my tank daily to feed creatures that consume silica, including diatoms.

Maybe silica sand causes blooms in some tanks, maybe in no tanks, maybe only when the sand is new, I don't know the answer.

 

[randy holmes-farley]

I certainly agree that it takes many nutrients to cause blooms of any kind.