DIY "Aragonite" Sand?

[lordofthereef]

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.

Thanks, I think this was the first bit of actual helpful information. :thumbsup:

Again guys, perhaps the METHOD at which I am trying to crush this stuff won't work... I don't know. The real question I have been trying to bring across though is whether or not it is even safe (as far as the health of a tank goes) to even try this.

 

[lordofthereef]

Do some searching, but I think you'll find it's not a great idea for a few reasons...

As I said, I found nothing, which is the main reason I asked here. Do you remember any of the reasons that it is no good?

 

[uncleof6]

Anecdotally, since oyster shell is calcium carbonate based, there really should not be any problem using it as a substrate. One of the big uses for it years ago, was for African Cichlid tanks, that need a very alkaline water quality. But then that would depend on the source of the oyster shell. The cheapest is sold as "chicken feed", but it has a rather high phosphorous content (Phosphates)

Grinding it up into sand is a good thought, because it does not look as a marine substrate should (opinion.) I would think though, that it would pulverize almost to a powder, rather than a "granular" type "sand." But even if it did become "granular," the shape of the grains would not be life friendly as it were-- being rather jagged, rough, etc. Basically such as silica sand, but that is just about the only drawback to the silica sand. A bio friendly grain would be the more "sphereical" shaped oolitic type substrate, which makes a more fluid sand bed, and bottom dwellers-- as well as infauna, are not abraded by it. (Without going into sand bed physics, mechanics, biology, chemistry etc.)

Suitable substrates for marine aquariums have been, still are, and always will be:

Aragonite (polymorph of Calcite)
Calcite
"Dolomite"
Silica sand
Oyster shell

Jim

 

[lordofthereef]

Thanks for the input Jim. Most of the searching I have done brought me back to using the oyster shell as cichlid tank substrate. The shells turning to dust instead of "sand" seems to be a common thought shared by nearly everyone here. Maybe when it warms up I will just make this a project of mine and see how it goes. If it ends up being just like silica as far as grain shape is concerned, then I guess I may as well just use a silica sand or go the expensive route

 

[kcress]

The normal way to make something a certain size is to run it thru a crusher that has spacing the size you want the result to be. Hence by definition anything that comes out the other side is less than the spacing. This isn't provided by a cement mixer with a bowling ball in it.

If you found a sheetmetal roller it could be pressed into this service. They consist multiple steel rollers that you set the spacing of and a hand crank that you could feel your way along with.

 

[hllywd]

As I said, I found nothing, which is the main reason I asked here. Do you remember any of the reasons that it is no good?

My search doesn't bring me back any of the old threads that seem familiar. Jim's explaination seems about correct as I remember previous discussions though. Although I did use a Southdown type substitute, I consider myself lucky not to have run into problems I wasn't able to/ didn't know at the time to test for. A buddy of mine has silica in a cube tank with an eel, a couple very happy RTBAs, and a pair of maroon clowns. The tank has been running for 3 or 4 years now without problem. I think the translucence of the sand looks odd, I wouldn't follow suit because of that. I do however believe it's a safer route than oyster shells due to the potential phosphate issue over time. Even at $1.00/lbs aragonite make a great looking sand bed and could be eliminated as a source of unexplainable problems down the road.

Tim

 

[lordofthereef]

I guess the issue I was having with the whole thing is that the aragonite doesn't necessarily eliminate the chance of issues coming from the sand bed, at least according to much of what I read. At the very least, it is safe to say that there are two VERY different thought processes and opinions when discussing a sand bed. If I am were to believe one side, the calcium based sands act as a buffer, and therefor do dissolve slowly over time. If I am to believe the other theories, calcium based sands are not subjected to a low enough pH for there to be any buffering/dissolving going on. In that scenario, whatever free phosphate there is could simply be washed, and whatever is bound in the structure of the sand, shells, whatever you want to call it won't ever escape. I was ultimately hoping that Randy chime in on what he thinks, since I believe he was the one who actually said there is no/very little buffering and dissolving of calcium based sand in our reef tanks due to pH. Granted he was talking about aragonite, but people are saying that the oyster shells need an even lower pH to dissolve (in the ca reactor media discussion), which would lead me to believe that they will be even tougher to dissolve.

 

[uncleof6]

The notion that aragonite "dissolves" under normal tank conditions, was born from the observation that sand in the lower levels of the sand bed would sometimes "solidify" so the assumption was that it was slowly dissolving over time. This has pretty much been discounted, and the culprit is most likely bacterial activity. They secrete glycocalyx, "slime" which cements the grains together. This same process plugs the pores in "live" rock, with no bulk water movement mechanism (critters living IN the rock rather than just on it) A lot of mis information running about with both sand beds and rock, positions defended almost to the death, and really is not worth the effort to combat it. Same with silica sand (quartz) disolving and leaching silicates into the tank. BAHHHHH.......

Jim

 

[lordofthereef]

Interestingly enough that dissolving factor was one of the first things that I "combated", at least in my mind, since bacterial population and production in marine environments was discussed (all-be-it to a very limited degree) in bacteriology. I think the problem is that these products have been sold as doing something they don't really do for so stinking long, and old habits die hard.

 

[lordofthereef]

http://www.advancedaquarist.com/issues/jan2003/feature.htm

Well, I found this by Randy about silica sand (specifically the mined "play sand") and am not feeling so confident about trying the silica sand anymore

 

[barderer]

I remember reading about people trying this before. As stated earlier the main problem was the cheap source material is heavy in phosphates. You could soak some powdered material in saltwater for a few weeks and then test for phosphates with a high quality kit to determine in your material is good. Once you get that all sorted out you still have this crushing problem which is far from trivial. E.G. its not worth your time man. You might be better off spending the time doing some deeper research on how to buy aragonite in bulk from "unknown" suppliers. Also, if you live near a beach you can often get crushed shells in perfect grain size where two breaks converge on the beach. It creates a little trap for crushed shells that have been washed over and over again in the current. Go in with an aquarium net and skim the wash as the current comes in. I have obtained many 5 gallon buckets worth of substrate this way. Its very beautiful and works well. Oh whoops just read the Iowa locale...no beach...

 

[lordofthereef]

You might be better off spending the time doing some deeper research on how to buy aragonite in bulk from "unknown" suppliers.

I looked into this and could get the sand for about $275 per ton, which is a fantastic price. Problem is I would have to purchase I think 50 tons at a minimum. The price includes freight, so it is a great buy no doubt but I really have no means of storing sand in such quantities LOL. I will probably just have to cave in and pay out the butt for the "name brand" sands.