[Dragonstar]

Is Dolomite the same thing as calcium carbonate?

I am doing a MTS substrate as recently popularized by Sean/AaronT/et al and have soil, clay, and muriate of potash. I could buy dolomite online and also buy kits here in the trade forum, but I want to learn something while doing this and also am having fun looking for it locally.

The Aqua Medic bottle description pictured on Aquacave reads "Pure calcium carbonate for use as a soil ground, as filtration media in sea water...." My LFS carries a very coarse sand/fine gravel that is white and labeled as 100% calcium carbonate. They sell it as a bed for crab terrariums. Is this calcium carbonate sand the same thing as dolomite? I thought dolomite was calcium magnesium carbonate, and not just calcium carbonate?

Also, I have very soft water, as listed below. This is a natural fit for an Amazonian tank, perhaps with Rams or silver dollars and the like. In that case, is the dolomite still recommended as an additive to the substrate? Thanks in advance, this one issue is causing me no end of confusion.

Substance, unit of measurement Annual Average
pH, standard units - range 7.5 – 7.7
Alkalinity, mg/L 27.0
Calcium, mg/L 5.3
Chloride, mg/L 16.3
Conductivity, micromhos/cm 201.0
Hardness - Calculated, mg/L 27.0
Hardness - EDTA, mg/L 27.0
Orthophosphate, mg/L (as phosphorus) 1.12
Potassium, mg/L 2.3
Total Solids, mg/L 133.0
Zinc, mg/L 1.02

 

[jfrank85]

Dolomite- CaMg(Co3)2 so its Calcium magnesium carbonate. I wouldn't use silver dollars in a planted aquarium due to their herbivorous nature. As long as the dolomite doesn't get into the water column it should be fine. Calcium is needed to build strong structures. The calcium carbonate in the LFS is probably aragonite or crushed coral used in saltwater or african cichlid tanks to provide constant high pH and also to provide calcium for the corals. Not sure if this is ok for a planted aquarium unless you were growing Vals.

 

[Dragonstar]

That's what I thought, it is calcium magnesium carbonate. So why does the dolomite that is suggested to use with a MTS substrate label itself as "Pure calcium carbonate?"

 

[Hoppy]

That's what I thought, it is calcium magnesium carbonate. So why does the dolomite that is suggested to use with a MTS substrate label itself as "Pure calcium carbonate?"

A mistake? But, a minor one.

 

[Dragonstar]

Thanks for the help, this is baffling since I don't yet have the experience to understand this method.

Clearly there is a mistake. I'm not sure what the mistake is. That's what I'm trying to determine.

Is this:
http://www.aquacave.com/dolomite-1-liter-by-br-aqua-medic-2176.html

...calcium magnesium carbonate (dolomite) that has been mislabeled as calcium carbonate? or is it calcium carbonate and the name "dolomite" is inaccurate?