play sand and silica for Randy

[BigJim]

Randy, I read your article on silica in the reef tank. Could you give me some more input?

If sand is silica (or silica is sand), how do you get silica free sand?

The sand they sell (which is supposed to be from the ocean) in petstores is over priced. The sand at hardware stores has silica in it and is not recommended for fish tank use.

How are the sands different?

I'm confused? Is it safe to use sand designed for a child's playbox in a reef tank?

This is an example of the sand that I was looking to use but a diiferent brand (from a local company)

[Genetics]

Silica is found in sand that you buy at a local hardware store. The sand for fish tanks is composed of ground-up calcium carbonate substrate from broken up pieces of the reef. Usually, it is labeled argonite or oolytic sand.

[Randy Holmes-Farley]

I saw the other thread and thought the answers there were good:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1516954

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. :)

[BigJim]

That explains the LFS sand and why there is no silica. Isn't the ocean made of sand? Wouldn't that contain silica?

[BigJim]

Randy, do you agree with greenbean36191?

I would be okay if using the play sand?

[Randy Holmes-Farley]

Isn't the ocean made of sand? Wouldn't that contain silica?

Those sorts of arguments are flawed. Nevertheless, I expect most silica sand is OK.

IMO, natural beach or river sand is a much better choice than man made ground up sand, as dissolvable bits are gone from natural sands, but not broken silica.

That said, I still add silicate to my system. :)

[BigJim]

Thanks. If I have any problems you can come over for weekly water changes! JK:rollface:

[Wind]

Does that mean SILICA concentration is higher in NSW? I just made a post. For reasons I suspect my 'too much' water change using NSW is causing bacteria bloom or something and not allowing my system to equalize just yet.

[therealfatman]

Usually the less processing done by man the better. Just like they are always finding rat hairs in processed tuna fish, they are always finding scraps of metal and other assorted garbage not natural to the area in which sand was harvested from. Even man screened sand is more contaminated than naturally water sorted sand.

Silicates, as the most important group of rock forming minerals, comprise the majority of the common minerals. However, when people refer to silica they are usually referring to Quartz (SiO2). Quartz is a very, very common rock-forming mineral and it is hard to find any place where there is sand where at least a small amount of silica sand is not present.

There are also many other rocks that are silicates, such as chert, garnet, talc and chlorite. Even most granites contain a large amount of silicates in the form of quartz. So to just discuss silica as laymen typically do is at times difficult as few people have much education in the field of geology or mineralogy so the discussion becomes pretty vague as it addresses just the one form of silicate, quartz.

Yes, I use both quartz and aragonite in my reef systems. When function and costs are a major concern I use quarts sand. Where appearance is more important than function and cost I use aragonite. I do use sifted/graded sand that is typically sold for sand blasting in deep sand beds. I use just play sand in RDSB applications. I must include also that I keep only SPS corals, no fish or critters, not even a clean up crew. I do keep a few such things in refugiums.

[Randy Holmes-Farley]

Does that mean SILICA concentration is higher in NSW?

Depends on the water, but it can be.

I discuss that here, as well as show measurements of silicate from both silica and aragonite sands:

Silica in a Reef Tank
http://advancedaquarist.com/issues/jan2003/feature.htm

[daveverdo]

Well, I'm not a geologist, oh wait I am, know the degree would come in handy.

From a geologic stand point the definition of sand is a sediment between 1/6 and 2 mm. The designation of something being considered sand makes no mention of composition. The composition of sand is usually determined by the source rock. Because silica (quartz) does not weather easily it is usually all that is left when streams carry sediments downward toward the ocean. SO in many large continental areas the lakes, streams, and beaches have silica sand. Most comercial sand is silica because it is readily available from quarries and is used in construction because of strength.

If the source of the weathered sediment is other than typical continental rocks than the sand will have different compostion. For example, many beaches in Hawaii and other volcanic islands have sand composes of volcanic based sands (basaltic) with higher iron and magnesium content. Many tropical islands formed from reefs (atolls) are composed of limestone and the sands produced are calcium carbonate.

Based on the geologic definition they are all sand.

Playsand has different composition depending on location. From what I understand quartz playsand is banned in California because they feel there are negative health risks. Playsand in California is typically ground limestone. Ground limestone playsand is available most place as "Premium".

The following thread may help:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1331876

Dave
PhD Geosciences

[HighlandReefer]

I have been through most of the stores in Maryland and all I could find was the silica based sand, except for the LFS. I know quite a few hobbyists who have used the silica based sand with no diatom blooms. I would go with the pure white silica sand rather than the browns.

[daveverdo]

Most Home Depot stores carry Pavestone. There are different versions at different prices. It is usually in the outdoor area with the garden supplies. Even though it is Calcium Carbonate it will still have a warning label that says it may contain silica. This covers any liability because of silica health risks. Some may actually say "Not for use in aquariums". Typically this is a good thing. The not for aquarium use is mainly addressed to fresh water aquaria where the calcium carbonate would not be good.

I have found the best way to check is bring a small jar of vinegar with you, find a bag with a hole in it (I do not condone making your own hole) spinkle a few grains in the vinegar and look for a reaction.

Another easy test is the Mohs hardness test. Calcite (calcium carbonate) is much softer than silica. Take a few grains and rub it on a piece of glass or steel. Silica will scratch the steel or glass, calcite will not.

Dave

[HighlandReefer]

I have not tested the Pavestone myself, but several of the hobbyists in our club have and stated that it did not pass the vinegar fizz test.

[daveverdo]

I believe the more expensive, High Desert Playsand, is the calcite based sand in our area of NY. Not sure if the Maryland Home Depot gets it from the same supplier.

Dave

[HighlandReefer]

Thanks for the info. I have not seen the High Desert Playsand yet. This is not the season, but maybe it will appear in the Spring. :)

[kgross]

What I have been using lately is a Dolomite sand, that is sold for making swimming pool concrete. It works great so far, nice and white, soft so it does not scratch like silica sand, and with no bad side effects yet.

Kim

[therealfatman]

<a href=showthread.php?s=&postid=13814233#post13814233 target=_blank>Originally posted</a> by daveverdo
Well, I'm not a geologist, oh wait I am, know the degree would come in handy.

From a geologic stand point the definition of sand is a sediment between 1/6 and 2 mm. The designation of something being considered sand makes no mention of composition. The composition of sand is usually determined by the source rock. Because silica (quartz) does not weather easily it is usually all that is left when streams carry sediments downward toward the ocean. SO in many large continental areas the lakes, streams, and beaches have silica sand. Most comercial sand is silica because it is readily available from quarries and is used in construction because of strength.

If the source of the weathered sediment is other than typical continental rocks than the sand will have different compostion. For example, many beaches in Hawaii and other volcanic islands have sand composes of volcanic based sands (basaltic) with higher iron and magnesium content. Many tropical islands formed from reefs (atolls) are composed of limestone and the sands produced are calcium carbonate.

Based on the geologic definition they are all sand.

Playsand has different composition depending on location. From what I understand quartz playsand is banned in California because they feel there are negative health risks. Playsand in California is typically ground limestone. Ground limestone playsand is available most place as "Premium".

The following thread may help:

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1331876

Dave
PhD Geosciences

A Geoscientist. Good to hear from you. Well written and pretty concise. I do miss the terms igneous, sedimentary and metamorphic that so much remind me of past geology courses.

You did not mention pyroclastic in there when mentioning volcanoes. Lots of high silica pyroclastic rock out there.

Silica sand (quarts) is liked by engineers because it behaves well with portland cement, because it weathers well, it stands up to abrasion and it is generally cheap. There are however many rocks that are high in silica that are not liked by engineers in many cases, such as the production of concrete. Rocks/sand actually typically undergo quite a few tests before they are widely used by engineers as nature can provide so many variable rock compositions.

Silica (quarts) sand is removed from pits or rivers typically, not quarries. Quarries are surface excavations where rock is removed from its natural location in the bedrock as stone production proceeds. A pit is a surface excavation where gravel, sand, or other loose or unconsolidated material is removed from its source. In most parts of the country there is usually plenty of silica (quartz) sand available naturally without having to crush stone to produce it.

The diameter (size) of sand is 2 to 1/16 mm, not 2 to 1/6 mm.

Silica only has to be looked at under a microscope to see why it is perceived in California as a heath risk. Under a microscope grains of quarts typically look like shards of glass. The only other real perceived threat is silicosis from continually breathing dry, very fine silica powder. This has been a problem for miners, but sand box children? Then one should consider that sandstone, granite, slate and coal are all common sourses of crystalline silica, so is short term exsposure to play box sand fine particles really a genuine concernable issue? The real issue is long term exsposure caused silicosis as experienced by miners. It is an occupational hazard.

Many reefers do not use guartz (silica) sand when they have sharks, rays, flounders, cucumbers or wrasses due to this shard like aspect of silica sand.

[Genetics]

Holy Dolomite! This thread is becoming informative.... :D

[MR LIMPED]

The sand you are looking for walmart sells it or use to sell it its made by a company called white castle or it is called white caslte cant remeber which one but i have had it in my tank going on 7 years now it is very white and sugar size and only costs $2.00 and some change for 50# bag and it passes the vinager test.I have about 800 or so pounds of this still in the bag i was going to use this in my 265 but it is going to be bare bottom i will sell it if any body is interested.

[daveverdo]

The diameter (size) of sand is 2 to 1/16 mm, not 2 to 1/6 mm.

My typo, sorry.

The sand you are looking for walmart sells it or use to sell it its made by a company called white castle

I believe you are talking about Old Castle. I don't think Old Castle is around anymore.

There is also Kolarscape another one that passes the acid test.

Dave

[MR LIMPED]

Its been awhile thanks...

[therealfatman]

There was a national chain pet store selling a name brand sand that claimed to be natural sea sand. It did nor fizz in the slightest when vinegar or hydrochloric acid was added to it. The national chain store stillo sells the companys products, but that one specific product is no longer sold. The company now sells Caribbean Live Sand. All sand should be suspect as long as carbonate sands are a high market price item.

One corporation in the Bahamas basically controls the price of aragonite sand anymore (at least in the USA). The bahamiam aragonite sand used to be delivered by ship to the east coast as building sand (Old Castle) so cheaply that it displaced the sands natural to the east coast markets. But then the aquarium hobby marketers got involved and now? Well now everyone pays dearly for aragonite sand.

The only cheap aragonite sand I am aware of sells in a minimum shipment of 2000 pounds, and only to persons with verifiable business licenses. It is sand from the Pacific not the Bahamas and it is sold through over seas suppliers.