# about Onyx sand



## Rek (Jul 19, 2005)

hi
i have read the composition of Onyx sand and i have see that there are more Magnesium

this can alterate water value? this value can be calculate before starting tanks?

i want use it whit osmosi water (gh=0 and kh=0)

tnk


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## trenac (Jul 16, 2004)

Not sure what you are asking... But Oynx sand can raise your Kh levels.


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