# Alternative for dolomite?



## lochaber (Jan 23, 2012)

Dolomite is a type of limestone that is a mix of calcium and magnesium carbonates. It's a bit less soluble then regular old calcite or aragonite (just Calcium carbonate), plus it also provides magnesium.

If you can't get dolomite, I imagine any other source of calcium carbonate should work somewhat- cuttlebone, crushed coral, limestone rock, etc.


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## wkndracer (Mar 14, 2009)

Is your source water carbonate weak?
Above 2dKH of water carbonate hardness I don't personally see the need for the additions.


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## DogFish (Jul 16, 2011)

Go to your LFS (Local Farm Supply) and get a bag of Chicken Grit, it's crushed coral and Oyster shells. Oyster shells are a source of calcium and magnesium.

I agree with wkndracer, you should consider your water perimeters. Also, consider the plants you intend to keep as you build your substrate.


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## marcnc (Dec 13, 2011)

Thanks both of you for the info. Sorry for delay had to pickup a new test.

So I tested it today and it right at 2dKH, so I guess the question is now should I add the Chicken Grit. As for plants, mix of plants, stems and roots.


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## marcnc (Dec 13, 2011)

Assume this is what I want? Seen several types. Waiting to see if you guys think I should add it or not?

http://www.tractorsupply.com/en/store/manna-proreg;-oyster-shell-5-lb


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## DogFish (Jul 16, 2011)

marcnc said:


> Assume this is what I want? Seen several types. Waiting to see if you guys think I should add it or not?
> 
> http://www.tractorsupply.com/en/store/manna-proreg;-oyster-shell-5-lb


I would think that would work. Check for any additives, really should be any in it that I can think of. The stuff I've bought can In a brown paper bag and I don't remember the label or logo.


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## lochaber (Jan 23, 2012)

DogFish said:


> Oyster shells are a source of calcium and magnesium.



I hadn't heard this before. I was under the impression that pretty much all of the mollusks produced shells of calcium carbonate (usually aragonite). Have any more info/specifics on this?


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## Diana (Jan 14, 2010)

I also thought oyster shell was CaCO3, not much (if any) magnesium. 
From Wikipedia, Seashell:
Because seashells are in some areas a readily available bulk source of calcium carbonate, shells such as oyster shells are sometimes used as soil conditioners in horticulture. The shells are broken or ground into small pieces in order to have the desired effect of raising the pH and increasing the calcium content in the soil


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