# Calcium sulphate



## chris1004 (28 Mar 2010)

Hi,

Is the gypsum thats used in beer making a suitable source of calcium sulphate for my remineralising agent? 

I'm specifically looking at the Brupaks brand at the moment as its a third of the price that AE are selling calcium sulphate for.

Regards, Chris.


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## dw1305 (29 Mar 2010)

Hi all,
I think the beer making version would be all right, but I'm not sure about using it, purely because calcium sulphate is virtually insoluble, particularly if it is the anhydrous CaSO4, the dihydrate CaSO4Â·2H2O is a bit more soluble.
cheers Darrel


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## chris1004 (29 Mar 2010)

Hi Darrel,

Thanks for the answer but it poses more questions.

AE sell calcium sulphate which is the CASO4 variety according to their website specifically for use in remineralising agents. 

http://www.aquaessentials.co.uk/calcium-sulphate-500g-p-561.html


Also I find it difficult to understand why it would be used in beer making if its not soluble. I'll admit the info from you has come as a bit of a body blow as it wasn't until I checked again the AE website that I have realised that I'm not following james's remineralising recipe to the letter as i thought I was. 

Regards, Chris.


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## JamesC (29 Mar 2010)

Gypsum is the dihydrate which is what I use and what AE and Fluid Sensor sell. It isn't that soluble but does dissolve in time. When first added to the tank it may create a milkiness for a couple of hours.

The other form is the hemihydrate which is plaster of paris. It gets hot when water is added to it.

James


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## a1Matt (29 Mar 2010)

I use gypsum (bought via ebay, packaged for use in brewing).
I dose it directly to the tank, it takes a while to dissolve, up to 5 min or so, but this is fine for me. The plants respond well to it!


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## chris1004 (29 Mar 2010)

JamesC said:
			
		

> Gypsum is the dihydrate which is what I use and what AE and Fluid Sensor sell. It isn't that soluble but does dissolve in time. When first added to the tank it may create a milkiness for a couple of hours.
> 
> The other form is the hemihydrate which is plaster of paris. It gets hot when water is added to it.
> 
> James



Hi fellas,

Please excuse me for being dumb but it appears to me that there is conflicting advice between James and Darrel here.  

In the link in my previous post it clearly states that the form that AE are selling is cas04 which according to Darrels post is not the dihydrate form that I should be using. 

Gypsum is the calcium dihydrate that I should be using. :?  :?  :?

So the beer brewing stuff will be ok then??????

I so hate chemistry......I just don't understand it.....Never did it in science at school took physics instead. 

What I'm currently using is the stuff from AE but I was hoping to save a few quid by getting it from a beer brewing suppliers instead. 

Regards, Chris.


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## dw1305 (30 Mar 2010)

Hi all,
The solubility is 0.0021 g/100 mL (20 Â°C, anhydrous) and 0.24 g/100mL (20 Â°C, dihydrate), so it is definitely the dihydrate you want.

As James says the natural form is normally the dihydrate ("Gypsum") and it will revert to the dihydrate form from anhydrous fairly rapidly if exposed to atmospheric moisture (unless you start with the CaSO4 mineral "anhydrite"). I wouldn't see any problem at all in using the brewing stuff. 
http://www.howtobrew.com/section1/chapter4-2.html

It's not really conflicting advice, when James says it goes "milky", this is the calcium sulphate coming out of solution, that residue will re-dissolve as soon as the concentration of calcium sulphate (as calcium Ca(2+) and sulphate SO4(2-) ions in solution) in the tank falls below the solubility point, so actually this is an advantage as a re-mineralising salt, you can't ever have much of it in solution as ions, but you can have a very large reserve of it available. 

cheers Darrel


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## chris1004 (30 Mar 2010)

Hi Darrel / all,

Thanks for the clarification in lamans terms  exactly what I needed. The chemistry bit still goes straight over my head but its irrelevant to me as long as I know I'm using the correct stuff and thanks to James the quatities to use them in. I think whats confused me is AE's webpage which lists the stuff as CASO4 which in your fist post you call anhydrous when in actual fact AE should have listed it as  CaSO4Â·2H2O the dihydrate.

Anyhow I'm going to get my next lot from a beer brewing supplier and save a fortune. The going rates from many of those suppliers is a quater of what AE are selling it for, but then I shouldn't be suprised as I've found exactly the same with all the other ferts / chemicals that I've sourced elsewhere. 

Here's a list of some usefull contacts I've found.

http://shop.ebay.co.uk/*alchymist*/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p3686

http://shop.ebay.co.uk/chem-star/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p3686

http://shop.ebay.co.uk/xpresschem/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p3686


The postage is usually a lot cheaper to.

Regards, Chris.


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