DIY "Aragonite" Sand?

[lordofthereef]

Now I know that if it isn't actually aragonite (dead coral skeletons), it isn't really DIY aragonite either. But I was thinking about crushed oyster shells versus aragonite sand. The oyster shells can be had for mere pennies per pound (or less) whereas the aragonite is incredibely expensive. My understanding is that they are essential the same compound, calcium carbonate, or CaCO3. What is to keep me from dumping a bunch of these crushed oyster shells into a cement mixer and allowing it to crush to even finer (whatever desired size) particles and use that as a sand bed? I feel there may be something I am missing here as there is not much I have found on the subject at all. Sure it might be a little more work, but it also beats paying up to $1.00/lb. for aragonite sand.

Also, can crushed oyster shells be used as calcium reactor media instead of paying an arm and a leg for aragonite chunks?

Any thoughts?

 

[Rhodes19]

The only thing that comes to mine is that it would turn out as dust instead of sand or gravel. I used crushed oyster shell to make my diy rock and there was a lot of dust in the bags. Try running a bag through and see what happens. HTH

 

[lordofthereef]

I considered that as well. I am still wanting to try this but would need to rent the mixer. Not a huge deal, as it would be a money saver in the end if it works out, but it has been -10 and lower outside recently LOL. Any other input is appreciated.

 

[ERICinFL]

I don't remember much from the Marine Biology class I took in college 18yrs. ago, but if I'm not mistaken, oysters develop their shells pretty much they same way corals develop their skeletons. I wouldn't see any issues with grinding it down to "sand". You'll probably end up with quite a bit of dust, but it should rinse away fairly easily. Considering the cost of oyster shell, even if you yielded just 20-30% "sand" from a 50lb. bag, you'd still be ahead. Of course that's not counting the labor.

 

[lordofthereef]

That's what I was thinking too. I figure there wouldn't be much more labor outside of plugging in the mixer and dumping in a few bags of shells and letting it run. I suppose there would be some extent of trial and error as to exactly how long I need to let it run. I imagine not long though as the shells seem pretty soft/brittle last I recall.

How about using this stuff as calcium reactor media? Any input on that?

 

[ERICinFL]

How about using this stuff as calcium reactor media? Any input on that?

I don't use one, so I can't give any input. You should probably ask the question in the reef chemistry forum.

 

[Rhodes19]

I considered that as well. I am still wanting to try this but would need to rent the mixer. Not a huge deal, as it would be a money saver in the end if it works out, but it has been -10 and lower outside recently LOL. Any other input is appreciated.

I guess I can't complain about our 20 deg temp down here. LOL

 

[salty joe]

Oyster shells might not be the same type of CaCO3 as aragonite. I think it has to do with the way the crystals are formed. If I remember correctly, different types of CaCO3 disolve at different PHs, with aragonite starting to disolving at the highest PH.

Might be a question for Randy Holmes Farley.

Also, I have heard - don't know for a fact, that oyster shells contain phosphate.

 

[lordofthereef]

I think I will also ask this question in the reef chemistry forum then and put a link to this thread. Thanks for the input guys.

 

[jenglish]

It is my understanding that oyster shell was not to be used in a calcium reactor due to levels of either silicate or phosphates... maybe both. I would think if you didn't want them in a reactor I would be hesitent to use as a major component of substrate.

 

[lordofthereef]

I don't really know the answer. My understanding is that not much, if any, of the composition of our sand be actually dissolves into the water due to pH not being low enough. I see what you mean about a reactor causing issues since it is actually dissolving the media. I don't follow why that would also be an issue when used as a sand bed?

 

[Rhodes19]

Also, I have heard - don't know for a fact, that oyster shells contain phosphate.

I'll let you know. I just put 200 lbs of diy rock I made with oyster shell into my 180.

 

[NanoReefWanabe]

i really dont think a cement mixer is going to crush the shells up any....you would be better off looking for a large, and i mean large mortar and pestle...i would also be worried that the newly crushed oyster shells would have a flatter grain and be more likely to settle out in the tank and become a packed brick of sand...

 

[lordofthereef]

I am not sure, but as soft as the shells are I really feel like the mixer would work. Again, I am not sure, but it was an idea. What method do they use for crushing up coral skeleton. I also do not really follow why it would become a pack of bricked sand any more than anything else? If you look att he particle shape of some of the more "rubbl-like) substrate it looks like flat chunks more than anything else, at least to me.

 

[lordofthereef]

I'll let you know. I just put 200 lbs of diy rock I made with oyster shell into my 180.

I know plenty of people do this without much issue. That is why I wonder if it is still safe to use as a substrate since it is not actually being dissolved. Reactor is pretty much out the question though at this point I think.

 

[lordofthereef]

Bump to see if anyone else browsing might have any input.

 

[lordofthereef]

I found this info about aragonite sand. Aragonite Sand Spec Sheet
Now I need to hunt for something similar for the oyster shells.

 

[Rhodes19]

I know plenty of people do this without much issue. That is why I wonder if it is still safe to use as a substrate since it is not actually being dissolved. Reactor is pretty much out the question though at this point I think.

I'm sure it is safe as a substrate. If you can get it into a small gain, the sand sifters should not have any trouble with it. As it is in the bag, it may cut or scratch the fish as they are digging in it. I think your right about it being out of the question in a reactor. I've been told by several folks that the ph has to be around 5 before the Ca leaches out of the crushed oyster shell.

 

[hllywd]

i really dont think a cement mixer is going to crush the shells up any....you would be better off looking for a large, and i mean large mortar and pestle...i would also be worried that the newly crushed oyster shells would have a flatter grain and be more likely to settle out in the tank and become a packed brick of sand...

I have to agree. Tumbling the oyster shells may eventually break them down, but you'll end up with dust, not the sugar fine particles you're looking for. Running them through the mixer will cause the shell pieces to abrade each other, not crush like you really need for this purpose. I've never really considered using them, but have seen it talked about from time to time to use them as a substrate and there was some issues why not to. Do some searching, but I think you'll find it's not a great idea for a few reasons...

Tim

 

[Names Brucey]

I am not sure, but as soft as the shells are I really feel like the mixer would work. Again, I am not sure, but it was an idea. What method do they use for crushing up coral skeleton. I also do not really follow why it would become a pack of bricked sand any more than anything else? If you look att he particle shape of some of the more "rubbl-like) substrate it looks like flat chunks more than anything else, at least to me.

The mixer by itself probably won't work but if you threw something in there with it to tumble with the shells and break them then you may have some success but I think the blades on the mixer will likely inhibit the shells from breaking up sufficiently. However, there is a piece of equipment that is used in soils laboratories ( I have one) called an LA Abrasion machine. It is essentially the same in pricipal as a mixer except it is a closed hopper that has large ball bearings in it. So when the material is placed in it and ran, everything is broken up. I would think you could reach out to a local engineering lab and ask them if they would run the samples for you. Should be pretty cheap. You could also have them sieve the product in the end to give you a desired grain size if you will.