# Epsom salts



## hypnogogia (7 May 2021)

Is this OK to use when preparing my EI mix?  Was given it by a gardener.


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## zozo (7 May 2021)

Yes, it is...


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## hypnogogia (7 May 2021)

zozo said:


> Yes, it is...


cool, thank you.  Was a bit worried about the percentages and wondering what the remaining 51.5% is.


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## zozo (7 May 2021)

hypnogogia said:


> wondering what the remaining 51.5% is.


I'm not 100% sure but since it's a Hydrate it will mostly be water... 

Mgo + SO3 = MgSO4 and the most common is the Heptahydrate that should make it MgSO4.7H2O the last part are 7(hepta) water(hydrate) molecules per 1 MgSO4 molecule.


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## dw1305 (7 May 2021)

Hi all, 


zozo said:


> I'm not 100% sure but since it's a Hydrate it will mostly be water...
> 
> Mgo + SO3 = MgSO4 and the most common is the Heptahydrate that should make it MgSO4.7H2O the last part are 7(hepta) water(hydrate) molecules per 1 MgSO4 molecule.


Whatever it says on the bag it will <"only be ~10% Mg"> when you use it, because of Marcel's (@zozo ) <"water of crystallization">.

cheers Darrel


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