What kind of sand?

crooper

Member
What kind of sand is good for a sand bed? Does the color or origin matter? What about sugar sand? I'm trying to decide what to put in my 100 gallon tank, and how much.
 

crooper

Member
I have a 100 gallon with a smattering of crushed coral, I want to take that out and switch to sand and add live rock. It will be a fish only with live rock and cleaning crew. I like the blennies that sift the sand. Other than that, probably clownfish and other colorful fish.
 
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thomas712

Guest
The answer here is aragonite sand. Many hobbyists have found that Southdown, Yard right or its apparent new name of old castle sand works very well for reef aquariums. This is due to it being calcium carbonate based, and with an excellent grain sizes makes for a good functioning sand bed. 1/8mm is very fine> 1/256mm to 1/16mm is considered silt, and less that> 1/256mm is considered clay.
Southdown seems to mostly contains very fine to silt size particles, and maybe a few larger than 1/8mm.
Other aragonite sands are available through many LFS. If it is aragonite it is good.
The trick here is to make sure that it is aragonite and not calcite sand as many different minerals have identical chemical formulas but wildly different properties. Aragonite is orthorhombic crystal and calcite is rhobehedral, scalenohedral or prismatic crystals
This means they have a different arrangement of atoms giving them different properties of density, solubility, hardness etc. They also tend to incorporate different trace elements, based on what best fits into their different crystal structures. Aragonite will substitute larger atoms such as strontium. Calcite grabs magnesium and iron. Aragonite’s properties are much more beneficial in a closed system.
It also seems that many have used Quick Crete play sand with success though it is not calcium carbonate based, but silica based instead. No this does not mean that you will have silicates in your tank.
Very Generally speaking Silica sand, lets say industrial style is a high purity quartz (SiO2) sand. Silica is a stable compound and will not leach silicates into your tank for it has no "sillicates in it. Depending on its chemical and physical characteristics, silica sand is used as glass sand, foundry sand, abrasives ..etc. Silica sand can contain tiny amounts of impurities, such as iron, manganese, chromium, calcium, or aluminum, and give the sand its color depending on how much of these impurities are contained within. So it depends on geographically where your silica sand comes from as to how much impurities it contains. If you are going to use silica sand look for white silica sand as it is much more aesthetically pleasing
A warning about silica crystals:
Silicosis is a disabling, nonreversible and sometimes fatal lung disease caused by overexposure to respirable crystalline silica. More than one million U.S. workers are exposed to crystalline silica, and each year more than 250 die from silicosis. There is no cure for the disease, but it is 100 percent preventable if employers, workers, and health professionals work together to reduce exposures.
So in other words do not breath this dust. FYI there is also a warning label required by the state of California that is required on silica play sand.
Ways to test sand to see if you might be able to use it in your aquarium:
Take a sample of your sand and test some of the sand with vinegar. If it bubbles/dissolves, it is calcium carbonate sand and should be safe to use.
Take some sand and pass a magnet over it or in it, it might come out with little metal shavings from processing, if it does I would not use it. Though I have heard of some who have with little poor effects. Iron can actually be a fertilizer for macro algae.
I'll let you chew on that for a while

Thomas
 

crooper

Member
I live in Seattle, so Southdown is not an option. But my local Lowe's sells Quikcrete playsand. You're saying that if this sand 1) bubbles with vinegar, and 2) doesn't stick to a magnet, that it's okay to use in my tank?
While I would rather pay less rather than more for sand, I'd rather not have everything die that goes in my tank. :) Would putting a bag of play sand plus a bit of aragonite and/or live sand work well?
I've done some reading on Fenner's website and they say either use a DSB of 4" or more, or a thin bed of less than 1" for looks. I'm aiming for the latter, so I think 50-70 lbs of sand would be good in my 100 gallon (48" x 18").
 
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thomas712

Guest
Originally Posted by crooper
I live in Seattle, so Southdown is not an option. But my local Lowe's sells Quikcrete playsand. You're saying that if this sand:
1) bubbles with vinegar, and
2) doesn't stick to a magnet, that it's okay to use in my tank?
3)Would putting a bag of play sand plus a bit of aragonite and/or live sand work well?
4) so I think 50-70 lbs of sand would be good in my 100 gallon (48" x 18").

1. If it bubbles with the vinegar the its aragonite, yes
2. If you don't wind up with metal shavings then yes it is good to use
3. Do not use anything other than aragonite IMO, IME. I've seen many who have used just Quikcrete sand and did not like the color of it at all, its usually dark.
4. I would go for 80 pounds in a 100 gallon tank. I used 80 pounds in my 90 and it was just perfect to reach the upper edge of my plastic edging on the bottom of the tank. About a 1.5 to 2 inch bed.
I could look up the sku number for Southdown, Yardright, Old Castle and you can see if your local Lowes, Home Depot, Garden Center could order it for you, only problem is that it is the wrong time of the season. Don't rule out the garden centers or even a Toys R Us.
Thomas
 
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