black beauty vs. tahitian moon.... please help!

[anemonelover]

I know that black beauty is nasty slag that should only be used for sandblasting... I looked around a lot, but I didn't find much guidance on how to tell the difference between the two visually.

Is it true that black beauty is highly magnetic? Would that be the one thing that would definately give it away over normal, *natural* black sand? Is there anything else that would give it away if I saw it in person?

BTW, is it ok to run an undergravel filter with black sand? I was planning on laying a vinyl mesh screen over the filter so that the sand doesnt get in there.

Please provide any insight you might have! Thank you

j

 

[Len]

I do not recommend either. Matter of fact is, I would avoid both in favor of pure aragonite sand (also sold by Caribsea, maker of Tahitian Moon). I know that black substrate has an aesthetic appeal for some people, but the two types of sands you listed are both non-aragonite based and possess little merit in promoting and stabilizing a marine aquarium.

Sand found on coral reefs are aragonite based. A simple rule of thumb: When in doubt, do what nature does

 

[Len]

As for the undergravel filter (UGF), I don't recommend running one. UGFs are wrought with potential long-term problems and aren't the filtration of choice for marine aquariums. A simple deep sand bed of fine aragonite sand is the popular method of biological filtration (and chemical buffering); it's what I use and recommend.

Here's a good read for someone starting out in reefkeeping:
http://www.reefs.org/library/newbieguide.htm

 

[anemonelover]

As for the undergravel filter (UGF), I don't recommend running one. UGFs are wrought with potential long-term problems and aren't the filtration of choice for marine aquariums. A simple deep sand bed of fine aragonite sand is the popular method of biological filtration (and chemical buffering); it's what I use and recommend.

Here's a good read for someone starting out in reefkeeping:
http://www.reefs.org/library/newbieguide.htm

Hi!

Yeah, I've actually checked out that link before. Thanks!

We are planning on using a fluval, sump refugium, etc (all the stuff one should use), but the tank came with a full sized UGF as well. What kind of long term problems have you heard it could create? I was thinking seeing it was already there that I could use it with everything else. I have heard very good things from a lot of marine books about using them in conjunction with a full setup.

Why do you believe natural black sand isn't as good as far as substrates go? Of course, it's not live sand... but other than that. Would love to hear all sides before deciding.

Thanks for you thought!

j

 

[Anonymous]

Have any of those books been written in the last 20 years? :lol:

I would leave out the UGF, if I were you. Skimmer and live rock/sand is all you need.

The main determining factor of sands effectiveness is grain size, I believe. Sorry, I am not familiar with those you mention. Aragonite sand may in addition supply some buffering capacity to the system, but I wouldn't consider it a major factor.

 

[anemonelover]

Have any of those books been written in the last 20 years? :lol:

I would leave out the UGF, if I were you. Skimmer and live rock/sand is all you need.

Hehehe...okay you guys... I'll leave it out :wink:

I'm still interested in using Tahitian Moon tho. Again, does anyone know if black beauty is really magnetic? There is a guy in my area selling his used black sand, but he doesn't know/remember which one it is. I want to go check it out, but I'm concerned that I won't be able to tell which it is, and it's obvious I can't go with that black beauty crud if I'm doing one of the two. I will consider regular sand as well, but I'm so drawn to black sand that I may have to give in to it if I find the good stuff.

 

[Len]

I don't know if it is magnetic or not (if it is, it probably has a lot of Fe in it which will promote algae growth). You can take a magnet to it at your LFS and see if anything sticks

Aragonite sand is a lot better then non-aragonite sand. To start with, it's composed of the very thing coral skeleton is made of. It leeches nothing bad (at least not in appreciable amounts) and buffers the system. It's also the perfect habitat for many microfauna and flora, as well as nitrifying and denitrifying bacteria. I would highly recommend you go with aragonite based sand or live sand and forego the "cosmetic" black sand. Your system will be much better for it.

 

[TheOgre]

True black sand would be crushed volcanic glass, and would not add anything to the system in general.....

 

[Anonymous]

My understanding:

I am rather skeptical of the amount of "buffering" provided by an aragonite sandbed.

First of all, you are dealing with only the uppermost layer of sand, not the complete volume unless you are somehow passing water through it. With that, cut your sand volume in probably 1/4 with a 4" sandbed at least - probably more if the sand is super fine.

Then, realize that an appreciable amount of buffering compound (CaCO3 mainly) will not be released from aragonite until the pH is well below sandbed surface pH (in a normal healthy tank anyway) which is less than 7.0. - ala Calcium reactor. The pH may be that low in the depths of the bed, but there is no significant current to bring the solution into the water column.

While there may be some buffering effect at first, that will quickly subside. Try an experiment: put a few cups of aragonite sand in a gallon of fresh RO. There isn't really any appreciable life, so buffer "demand" can be considered quite negligible. Test the ph and Alkalinity. Let it sit for a week, test again and change half the water. After another week, test the water and change it again. Do this for a month. I'd be very interested to see the alkalinity readings you get after a month or two.

If there were any significant buffering effect in an actual system, we wouldn't spend hundreds on calcium reactors and supplements to maintain the constantly declining Ca and CO3 levels inherent in our systems. With that, the buffering capacity of aragonite, IMO, is quite irrelevant.

 

[anemonelover]

Len: yes, I read on another message board/net board that because black beauty is "leftover" from copper mining, that it is high is Fe and other metal residue. The users there also mentioned that it was sharp and dangerous, and responsible for killing a few fish that sift through substrates. Scary that any pet store would carry this stuff

TheOgre: but would it be taking anything away? Aside from the obvious live sand vs. not... live... sand (I'm not sure what else to call it :lol: ) ... do you think it would be taking anything away from the system?

Graham: Now you've thoroughly confused me... everyone is saying crushed coral base and aragonite sand on top :lol: I'm guessing that it's at least slightly better to have aragonite as opposed to *not* aragonite... but I don't know enough about that to speculate. Perhaps Len can help!

Thanks!

 

[Len]

Gradient differentials should be adequetely drive water in either direction, I think. There needn't be active flow to move waters of different concentrations. The pH just 1/2" into the substrate is significantly depressed, and when we're talking about a 3-4" deep substrate, that's quite a big buffer zone. I know when Dustin was working at Aquarium City in California, he told me they had to replace large quantities of aragonite substrate in their famous SPS tank on a semi-yearly basis, even with kalkwasser and MTC Pro-Cal in operation. FWIW, this rate isn't anything like the ones I see in my tank (I've only "topped off" my substrate 5 times in 8+ years).

My personal experience tells me argaonite substrates effectively stabilize pH and alk, but doesn't do much in terms of raising pH or alk for either. In my previous 50 gallon, I set it up with only a 1/2" coating of substrate for cosmetic reason. The pH gradually began declining over time to 7.9-8.0 (organic acculumation and decay) so I finally decided to add more aragonite - going against the popular substrateless methodology of the time. I noticed my pH stopped dropping but was disappointed it did not rebound. Next logical step was to start kalk drip, which obviously worked to bring pH back up to about 8.4. But kalk became too time-consuming and laborious, so I stopped its use abruptly. To my surprise, the pH remained very steady at about 8.3 afterwards. I know I can be misinterpretting this anecdotal experience, but baseline reasoning convinced me aragaonite-based substrates work at buffering the system.

 

[Len]

Graham: Now you've thoroughly confused me... everyone is saying crushed coral base and aragonite sand on top :lol: I'm guessing that it's at least slightly better to have aragonite as opposed to *not* aragonite... but I don't know enough about that to speculate. Perhaps Len can help!

j,

If the black sand is byproduct of copper mining, that alone should be enough concern. Copper and invertebrates don't mix. It's fine for freshwater fish and plants, but not corals, clams, crabs, shrimps, etc.

I don't know many people who advocate using crushed coral anymore. The particulate size is just too large, making it a poor choice to create an anoxic zone as well as a poor habitant for burrowing species. Most people now use fine aragonite exclusively.

 

[Robin Goodfellow]

...he told me they had to replace large quantities of aragonite substrate...

hi.
Len, notice that he said replace. It can mean replace the sand that "disappeared," or to scoop out some of the old sand, and put some new sand back.

I never talked to Dustin, but I gather that it means the latter???

You can tell by my tone of voice that I doubt that substrate actually dissolve in any significant degree in a tank's life time.

 

[Len]

Nope, Dustin said their substrate actually dissolved at a rapid pace. I'll see if I can get him to comment here.

I know mine dissolves, but nowhere near the rate Dustin described to me before. I've only added about 60 lbs of sand to date to counteract what's dissolved in my decade old tank.

 

[Anonymous]

Yeah, if you put aragonite over CC you will eventually probably end up with the large grains making their way to the top, and there's no benefit to it anyway. Leave out the CC.

Although I sort of poo-poo'd buffering capacit of arag, I should say I use only that. Its just most tasty. Also, my last reef over the course of a few years had the arag bed shrink by a couple of inches. Unless the fish were eating it, it must have buffered the water somewhat.

By-product of copper mining... yoiks!

 

[Anonymous]

ps. I always wondered if my cuke had a low-ph gut...

 

[anemonelover]

Yeah, that's why I was saying I didn't want the black beauty, which was the reason I posted... that stuff is pretty nasty and seems like it shouldn't be used in any tank because of it's sharpness.

I got the impression that crushed coral as a bed under the sand is good for filtration, but perhaps they were incorrect. Thanks!

 

[Robin Goodfellow]

hi.

By-product of copper mining... yoiks!

The label reads "99.94% copper-free" :roll:

Rather the "disappearing" of sand is due to settling effect or biological works (stomach acid of cuks, and Dan mentioned) or read dissolution is a interesting topic. My gut feeling is that aragonite dissolution process lacks either the equilibrium or kinetics in a usual reef tank for it to dissolve in any significant degree. (BTW, very few people has tank that runs more than a decade old)

 

[DustinDorton]

When I was at Aquarium City I was constantly replenishing the sand. As Len said, it was getting a lot of kalk (5 gallons a night in a 225) and had the mtc pro-cal on it.
One time we topped it off with geo-marine mix and we had a lot of clumping, we switched back to fiji live sand after that. We were replacing at least 20lbs every couple of months. I don't know why the sand dissolved so fast in that tank. I never really thought about cukes dissolving the sand, there were at least a dozen tiger tails in there. There was a LOT of coral in there, the calcium demand was massive, and the pH was rarely over 8.1. Perhaps biogenic decalcification? I have run some systems recently where the shells are dissolved right off the backs of snails.
Next time I go out, I will have to ask how often they are adding sand now, I was suprised to see how deep the sand bed was when I was home in May.

 

[anemonelover]

The label reads "99.94% copper-free" :roll:

Hey now, just passin' on what I read elsewhere! hehehe. I don't know if it actually has a whole lot of copper in it, but it is used for copper mining. To be exact in what I read (this is the part that caught my attention):

"Black beauty sand is actually Metallic Slag from the manufacturing
of copper. It is described as 32-45% SiO2; 25-33% Cao + Mg0; 24-35% Fe0. Wondering if the FeO would be a problem, I put about a teaspoon in
a very small jar with some water, shook it up, then tested the Iron content
using a seachem test kit. The results of the first test was 1.0 ppm. I
repeated the test and got 2.0 ppm. This is about 10 to 20 times too much!"

The corresponding responses concurred on the origins (ranging from just manufacturing to mining). In any case, if anyone has any other thoughts on the differences (visually) please chime in. Thanks again.