# good source of calcium carbonate ?



## spypet (Jul 27, 2007)

my tap water is very low in KH(1) and GH(1) so I'd like to raise them together using calcium carbonate.
I used Baking Soda(KH) and Seachem Equilibrium(GH) to control KH/GH separately, but I'd like to unify them.
is this ground limestone rock a good cheap aquarium safe source of this compound, and if not,
what other cheap but pure aquarium safe source would you suggest - please provide a link.


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## frozenbarb (Feb 8, 2007)

Tsk tsk.. Coke..

Same with me, But is there a way Lower PH without Lowering my KH,GH


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## Edward (May 25, 2004)

Hi spypet
Ca and KH can be increased by CaCO3 Calcium carbonate. Takes two days to dissolve and the increase is 1 to 1 ratio. 1 dGH to 1 dKH. Or you can use CaSO4 for Ca and baking soda for KH, both dissolve in minutes.

But the question is why? Who needs KH and high pH? Only special fish like African Cichlids. Most South American fish love low to no KH and low pH. Plants don't care about it either, most do actually better in low KH low pH environment. 

So, keep it simple. First, forget about KH and pH. CO2 alone can not push pH too low, it is just too weak to do so. But make sure you don't poison your fish with high CO2 levels. Then test your GH. Maintaining GH of 3 - 6 degrees with CaSO4 dose will do the job. CaSO4 can be obtained form chemical supply stores and www.plantprod.com as Gypsum-Calcium Sulphate. This product dissolves in minutes and does not change KH or pH. Plants and snails love it, especially Tonina. 

Thank you
Edward


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## spypet (Jul 27, 2007)

Edward, thank you for considering my question.
I gather from your answer that I can continue
using Seachem Equilibrium to keep my GH 3-6,
not worry about my low KH as long as my PH
does not get too unstable. Since I'm using
DIY Co2 there is no risk of poisoning my fish.
Once my S.Equilibrium runs out, I'll use CaSO4 
instead if I can ever find a small quantity seller.

do KH, GH, or PH levels do anything to help
discourage algae growth? or if they did,
that might also harm your plants, right?

do shrimp have any particular KH, GH, PH
preferences? my tank often kills shrimp,
and I suspect my soft water has something
to do with it. (besides copper & predation)


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## Edward (May 25, 2004)

Hi frozenbarb
Water pH can be safely lowered only by CO2 injection. This is in plant only, no fish aquarium. If you have fish or any fauna present you need to make sure you don't poison it with high CO2 levels > 30 ppm. So the lowest pH is set by KH level. See FAQ CO2/KH/pH table. 

Examples of the lowest pH limit due to high KH.
7.0 pH at 10 dKH 
6.7 pH at 5 dKH
6.5 pH at 3 dKH
6.0 pH at 1 dKH
5.65 pH at 0.45 dKH
5.65 pH at 0 dKH, the CO2 natural limitation ends here at safe pH level

At zero KH you can blast CO2 injection without any risk of overdosing it.

Thank you
Edward


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## Edward (May 25, 2004)

Hi spypet
I can't comment on Equilibrium because we don't know what the substance is. 



spypet said:


> Since I'm using DIY Co2 there is no risk of poisoning my fish.


 Not exactly true. Many DIY CO2 reactors work better then original products. 



> do KH, GH, or PH levels do anything to help
> discourage algae growth?


 No.



> do shrimp have any particular KH, GH, PH
> preferences? my tank often kills shrimp,
> and I suspect my soft water has something
> to do with it. (besides copper & predation)


 They need more Ca to build and maintain strong exoskeleton


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## Homer_Simpson (Apr 2, 2007)

spypet said:


> .. I'll use CaSO4
> instead if I can ever find a small quantity seller...


Sorry to hijack this thread, check your local wine/beer brewing supplies shop for CaS04. I was finally able to track some CaS04 this way. Apparently calcium sulphate is used to add permanent hardness (calcium ions) to brewing water for beer making. It was much cheaper than ordering it on-line considering the shipping costs involved. Monitor your GH carefully when you dose this stuff. It doesn't take much to cause your GH to sky rocket and if you are not careful, it is easy to overdo it and end up with too high a GH.

Regards


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## spypet (Jul 27, 2007)

Edward, thanks again for your time.

I'll be sure to give Gypsum a try to
raise my GH and benefit my inverts.



just out of curiosity, do you have an opinion
pro/con on dosing Calcium with the use of;

Calcium Nitrate - might help if you are normally dose extra NO3 separately
or
Calcium Chloride - too much Chloride is suspected to stunt plant growth.


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## taekwondodo (Dec 14, 2005)

CaSO4 is the same thing as Plaster of Paris.

http://en.wikipedia.org/wiki/Plaster

2CaSO4·4H2O → 2CaSO4·H2O + 3H2O

Easily obtainable at Home Depot, Lowes, or your local craft store.

1 gallon box will be ~$10 and should last an eternity.


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## Edward (May 25, 2004)

taekwondodo said:


> CaSO4 is the same thing as Plaster of Paris. Easily obtainable at Home Depot, Lowes, or your local craft store. 1 gallon box will be ~$10 and should last an eternity.


 &#8230; and it may come with additives that kill fish.


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## decebal (Jun 21, 2006)

I just bought 400g case of Plaster of Paris from Rona for $2.99. 
All it says on the box is First Aid Treatment: Contains: Calcium Carbonate, Calcium Sulfate and Crystalline Silica. 
 i don't know if i can use this stuff in my tanks.

Thanks,
D

I just found the composition http://www.dap.com/docs/msds/english/00071008E.pdf:

SECTION 2 - COMPOSITION/INFORMATION ON INGREDIENTS |
|-------------------------------------------------------------------------|
WT/WT %
ITEM ------------ CHEMICAL NAME ------------- CAS NUMBER RANGE
---------------------------------------------------------------------------
Calcium Carbonate 1317-65-3 15.0-25.0 %
Calcium Sulfate 7778-18-9 75.0-85.0 %
Crystalline Silica 14808-60-7 0-1.0 %


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## taekwondodo (Dec 14, 2005)

Edward said:


> &#8230; and it may come with additives that kill fish.


Well, I've been reconing water for over 15 years with CaSO4 from Plaster of Paris - _never _had an issue (Even checked with the vendor... pure CaSO4).

I'll bet I've killed more fish od'ing Stump Remover


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## Glouglou (Feb 21, 2006)

> I just bought 400g case of Plaster of Paris from Rona for $2.99.
> All it says on the box is First Aid Treatment: Contains: Calcium Carbonate, Calcium Sulfate and Crystalline Silica.
> i don't know if i can use this stuff in my tanks.


Calcium Carbonate will add Ca (calcium) and will increase KH, Calcium Sulfate will add Ca and sulfate is needed by the plants

but Crystalline Silica I will be suspicious about it because silica help the diatom algae to trive...



> Having said that, however, some diatoms are apparently capable of pulling silica out of glass or quartz, and if when culturing phytoplankton in glass containers, additional silicates are usually not added to the culture medium because the algae seem to get what they need from the walls of the flask (hence to common observation that diatoms grow fastest on the walls of the aquarium). Even with the presence of lots of dissolved silicate in the tank, however you still need the other nutrients (nitrates and phosphates) to get a bloom of diatoms. In fact, diatoms turn out to need *more* nutrients in culture (people generally also add glutamate & glycerophosphate to culture media to really get diatoms growing well) than standard microalgae. If there are high silicates but undetectable levels of nitrates and phosphates, you're still unlikely to ever get a significant increase in diatom growth. Some people *do* report having diatom blooms with silica sand (although the cause for such blooms is unclear). Stories about "I used quartz beach sand and the diatoms exploded in my tank" may be coincidence, it may be that the diatoms were already there growing on the glass, but the addition of sand gives them more surface area to inhabit and therefore they seem to bloom, or it may be that by using the beach sand, those diatoms were *introduced* to the tank in the first place. I think that the "dreaded diatom bloom" is as likely to be attributed to the introduction of the diatoms as to the provision of nutrients...


You should go with CaCo3 or CaSo4 it's probably safer


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