Current Southdown-equivalent sand is...?

[Anonymous]

I know Southdown isn't Southdown sand anymore...but where to get something similar for $4/bag?

Anyone?

Peace,

Chip

 

[Anonymous]

Do they even sell it anymore?

I know it changed to "Old castle" at one time in it's life... but I could have sworn that some reef supply company bought out the company (mostly so they can prevent people from getting their $4 bags of sand and instead charge them $40)

 

[Anonymous]

If that's true, that sucks. I don't feel like spending $60 for the sand for my tank.

Dammit.

Peace,

Chip

 

[Anonymous]

Yep. No more $4 sand. I went with ESV because I got a deal. If you use it, be careful, it sucks out the MG in your tank water. I had to dose close to a gallon and a half over the period of two weeks to get it back to normal.

B

 

[Anonymous]

So I'm curious, why are people still using aragonite sand? The rumors about it being a buffering agent and the like still floating around?

 

[Anonymous]

So I'm curious, why are people still using aragonite sand? The rumors about it being a buffering agent and the like still floating around?

Fine grade aragonite is preferred for worms and such over other available stuff...

 

[Anonymous]

So I'm curious, why are people still using aragonite sand? The rumors about it being a buffering agent and the like still floating around?

OK, smug scientist fellow P), enlighten the proletariat.

 

[Anonymous]

Add another generally similarly pedantic proletariat to that list. I used it in most of my hard-water systems when I didn't want to use crushed coral (which was most of the time) or gravel.

Edit: Never mind. I used dolomite.

 

[Anonymous]

So I'm curious, why are people still using aragonite sand? The rumors about it being a buffering agent and the like still floating around?

Fine grade aragonite is preferred for worms and such over other available stuff...

Bah, worms are over rated I want tough critters in my tank, nothing with little soft underbellies I was specifically referring to silica based brethren, which IIRC read that the idea of silica from the sand itself lending to diatom growth was also shown to be inconclusive.

So I'm curious, why are people still using aragonite sand? The rumors about it being a buffering agent and the like still floating around?

OK, smug scientist fellow P), enlighten the proletariat.

Just that the pH levels low enough only occur really low in the sand bed, and typically are not of any great amount to actually increase the pH of your tank. Also might be some phosphate issues with using sand as a buffering agent (I might be wrong on this account)

 

[Anonymous]

I thought the point about aragonite was that it starts to dissolve at pH levels over 8.0, which isn't that unusual in a normal, whereas calcite substrates need to be under 8.0, where the acidity increase isn't great for the life in the tank.

 

[Anonymous]

Aragonite is calcium carbonate, more specifically its probably parrot fish poop when they eat coral. If it dissolved at a pH over 8.0 then all the sand in the tropics would dissolve!

 

[Anonymous]

Doesn't it? I mean, slowly and eventually?

 

[Anonymous]

Well I'm not a chemistry buff so I had to wikipedia this for calcium carbonate.

Initial pH 	      0.00 	1.00 	2.00 	3.00 	4.00 	5.00 	6.00 	6.79 	7.00
Final pH 	        6.75 	7.25 	7.75 	8.14 	8.25 	8.26 	8.26 	8.26 	8.27
Dissolved CaCO3  	50.0 	5.00 	0.514 0.0849  0.0504	0.0474 0.0471  0.0470   0.0470
(g per liter of acid)

So it seems that at a pH of 7.00 it will dissolve but only at a rate of 0.047g per liter, and as mentioned those pH ranges don't get that low in the living space of the aquarium, and in very minimal amounts deeper down in sand bed. It doesn't show what it'd do for 8.0 pH, but I'm guessing even less, since it seems to be heading towards a pH of 8.27 or so it'll dissolve but again not much at all. But who knows, maybe that's normal

 

[Anonymous]

You would need to have unreasonably low levels of Ca or Alk at normal pH of an aquarium in order for CaCO3 to begin dissolving. The low end of what we consider "acceptable" Ca and Alk values means CaCO3 is supersaturated.

 

[Anonymous]

So it is wrong to say that aragonite differs from other calcium carbonate substrates? How come sand beds of aragonite shrink over time?

 

[meathelmet2]

You guys are way too advanced for me. I use sand cause it looks better than crushed coral.

 

[jamesw]

The oolitic sand (like Southdown) is actually precipitated via chemical process and lands in the Bahamas. I think the "mine" where the Southdown was dredged from is near Ocean Caye or nearby. If you do a google earth or maps search of Grand Bahama Bank you can see hundreds of miles of this sand forming a HUGE bank about 90 miles off Ft. Lauderdale.

Cheers
James

 

[Anonymous]

So, to answer my original query, the only way to get an oolitic sand bed is to buy the sand from the LFS?

Peace,

Chip

 

[Anonymous]

So it is wrong to say that aragonite differs from other calcium carbonate substrates?

No. The crystal structure is different.

How come sand beds of aragonite shrink over time?

Do they? I've always heard this but was never sure it was actually occurring. I guess it could be due to a localized low pH deep in the sand bed.

 

[Anonymous]

So, to answer my original query, the only way to get an oolitic sand bed is to buy the sand from the LFS?

Peace,

Chip

Yes. Although I don't know why you would want sugar fine sand in your reef tank in the first place...