Where does 'crushed coral' end and 'aragonite' begin?

[WinnipegDragon]

Correct me if I am wrong, but aragonite sand is basically just Calcium Carbonate right? Crushed coral skeletons are just Calcium Carbonite as well, right?

So is it just the sizing of the grain, or is there another difference between the two?

[Juruense]

Crushed coral is generally at least 3-4 millimeters.

Sand is generally 1 millimeter or less.

Use sand not crushed coral.

[WinnipegDragon]

What if what you have is *clearly* sand, but is labeled as crushed coral, i.e. coral crushed to 1mm or less? I guess what I'm after is the actual difference in material composition if there is one.

[Jen D]

If the crushed coral was pulverized to make the pieces smaller, then there are probably jagged edges on the pieces. Actual sand would be smoother, round pieces. That might be a problem for sand-dwelling species.

[WinnipegDragon]

Hmm, good point on that.

I'm starting my 20g nano and that's kind of where this question arises from. My LFS had bags of "#0 Crushed Coral Sand" and they look and feel like any aragonite I've ever seen. It's not sugar fine, but it's certainly not 'crushed coral' by any measure.

[Randy Holmes-Farley]

Aragonite is a specific crystal form of calcium carbonate. Calcite is a different crystal form. Neither say anything about the bulk size of the material.

These large crystals are aragonite, for example:

[Jen D]

I don't think that there is a difference in the chemical composition of crushed coral and aragonite sand. Aren't they the same thing?The sand is just processed by nature into finer grains. I could be wrong.

[WinnipegDragon]

The king of Reef Chemistry! Thank you for gracing my thread with your presence!

This leads to the next big question. Is crushed coral, assuming it has been properly reduced to sand-sized particles, better or worse that manufactured Aragonite sand in a reef aquarium?

[WinnipegDragon]

Originally posted by Jen D
I don't think that there is a difference in the chemical composition of crushed coral and aragonite sand. Aren't they the same thing?The sand is just processed by nature into finer grains. I could be wrong.

I don't think aragonite sand is actually gathered anywhere. I'm pretty sure it's manufactured...

[seapug]

The main components are the same thing chemically, but "crushed coral" is typically over 1/4" and sometimes contains pieces of shells and misc. non-aragonite (calcite) pieces in it. What we typically refer to as "aragonite" in the hobby is usually 100%, naturally fine ground calcium carbonate coral skeletons without any shells or calcite. Oolitic sand is Aragonite that is a very small, spherical particle size/shape.

[WinnipegDragon]

I'll have to get the brand name on the bag and post it here. It has to be 1mm or less.

[greenbean36191]

Is crushed coral, assuming it has been properly reduced to sand-sized particles, better or worse that manufactured Aragonite sand in a reef aquarium?

The grains may be shaped differently, but it makes essentially no difference in the functioning of the bed or the diversity of life that lives in it.

BTW, most of the fine aragonite sand in the hobby is a natural product. It's dredged in the Bahamas and barged over to the US where it's dried and sifted.

[WinnipegDragon]

I did not know that.

[Shnabbles]

I use Aragonite in my system... is this why i get alot of the stuff seriously clumping together, and becoming part of the rocks?

i mean it being Aragonite and with the mixing of my 2 part... does it being Aragonite be a big player in this?

[WinnipegDragon]

Sand will clump as the bacteria grows in it, unless you have a variety of sand-sifters anyhow.

[Shnabbles]

This isnt clumping.... this is becoming a solid rock.

[cjtice]

I have read in a tread (I think FW when i was messing with Cichlids) that Aragonite sand will clump if, (and this is where I forget the exact details) PH is off or some other parameter. I guess all it was saying is that you put aragonite into your system for a buffer and there is some type of reaction that causes it to clump, but I dont believe that I ever heard of sand becoming a solid rock.

[Jen D]

Originally posted by greenbean36191
The grains may be shaped differently, but it makes essentially no difference in the functioning of the bed or the diversity of life that lives in it.

My concern was that any un-worn, jagged edges could scratch sand-sifting fish or conchs. I've seen people say this about silica sand scratching sand-sifting gobies gills, for example. It's just a general concern/thought, since I don't know what his planned stocking list is.

[WinnipegDragon]

I don't know what it is either

Blue Spot Jawfish is a possibility, so burrowers are a concern.

[Jen D]

I plan on having a jawfish in my tank, too, so I've been having the same debate with myself about what kind of substrate to use.

[Randy Holmes-Farley]

Here's a thread on what is happening when sand hardens:

http://www.reefcentral.com/forums/sh...readid=1521274

[buffalo123]

If you place crush coral in a tumbler long enough you would end up various size sand with smooth edges.

[Jen D]

That's true. I wonder how long that would take, though, and who has a tumbler that could be used. I suppose a bucket with really good water flow would work as a tumbler.

[Jen D]

Originally posted by WinnipegDragon
I'm starting my 20g nano and that's kind of where this question arises from. My LFS had bags of "#0 Crushed Coral Sand" and they look and feel like any aragonite I've ever seen. It's not sugar fine, but it's certainly not 'crushed coral' by any measure.

I just went back to the top and you (WinnipegDragon) stated that the bag said "#0 Crushed Coral Sand". I wonder if that's just another way of saying it's regular old sand. CaribSea, for example, sells "Special Grade Reef Sand".

[WinnipegDragon]

Yeah, that's how this whole thing started. I really wanted to know if I have finely crushed coral, or the equivalent of aragonite, and whether or not it matters?

When I get home, I'll post a picture of the bags and we can all argue about it