Will Southdown sand buffer PH?

[SaltyMember]

I am preparing to set up a 7 gallon minibow and I have been reading alot of posts from people who recommend Southdown play sand for their sand beds.  I live in Southern New Jersey and am fortunate that all the Home Depots around here seem to keep it in stock.  It is inexpensive approximately $4.00 per 50 lb bag, so I would like to use it.  My concern is that I am not sure what it is....is it aragonite or some other calcium carbonate based sand?  Will this help to buffer the PH?  

Anyone with info on this?  Thank you.

[Kapelakin]

Southdown is the same thing as aragonite from the LFS.  The thought now though is your tank has bigger problems if it's relying on the substrate for pH buffering.  Many people are using silica based sand for DSB's now with good results.

 

HTH

[jjharrisx4]

The idea that the calcium based aragonite may help to buffer our tanks is creative, but in all actuality not true.  Many people feel that since aragonite is used in a calcium reactor to raise alkalinity, ph, and CA levels it would, naturally, help these parameters in our systems even w/out the reactor.  Actually, the PH in our systems is much too high to see any appreciable or measurable buffering from aragonite (southdown).  In a CA reactor, the introduction of CO2 gas lowers the PH to below 7, making it acidic.  This in turn breaks down the aragonite, crushed coral, or other media to release the CA that we desire.  Hope this helps.

 

Like Kapelakin said, if your tank is relying on the substrate for buffering you'll have much bigger problems to deal with.  Good luck!

[Leonard]

It should be noted that due to biological activities within the sand bed, the pH signifcantly decreases below the surface of the substrate.  Aragonite-based substrate, in fact, does help buffer the carbonate levels of the water.

 

I've performed a uncontrolled study several years ago (when "true Berlin" substrateless systems were the rage) and found that generally speaking, aquariums with aragonite-based substrate did exhibit greater buffering potential.  All anecdotal, I know, but by theory and observed practice, my conclusion is calcium sandbeds do buffer alk and pH levels.

 

Southdown is aragonite, mined from the same station as Caribsea's products, but with less quality control (impurities abound) and grain consistency.

[Toyfreek]

In a deep sand bed there is some buffering due to anarobic zones within the bed. In a nano system I doubt you will ever see any effects from an aragonite Bed. I would like to see your study though leonard. how did you perform the testing?

[Leonard]

The study wasn't a controlled experiment.  It was a comparative analysis of pH and carbonate hardness levels based on numerous anecdotal reports from about 2 dozen hobbyists.  Again, far from from scientific, but interesting nonetheless.  I did it primarily because substrateless was in vogue, and I had always believed substrates were beneficial to reef aquariums (ie, I sought support to debunk the methodology).

 

It should be noted these weren't "nano" tanks.  Depth of substrate, however, should play a more important role in buffering capacity then volume of tank (although of course, there are relationships).

[gabe3eb]

Well, I will give my two cents on the silica vs. southdown. Silica sands have silicates in them which are like small pieces of glass and they foster algae growth massively. I mean the brown type, which isn't that pleasing to look at in a tank IMO. The southdown does not have any silicates in it and I am speeking from experience here. I have set up two tanks with silica sand and one with southdown, I am liking the southdown a lot more with my new tank. But, on my new refugium, I will most likely use silica because I already have a tank with some in and I wont need to seed it, plus it will allow for more algae growth. HTH,

gaber