They include a number of minerals there and you can figure out what percentage of that would be your hardness minerals (calcium, magnesium and iron).
1	They	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	2	nsubj	2:nsubj	_
2	include	include	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	0:root	_
3	a	a	DET	DT	Definite=Ind|PronType=Art	4	det	4:det	_
4	number	number	NOUN	NN	Number=Sing	2	obj	2:obj	_
5	of	of	ADP	IN	_	6	case	6:case	_
6	minerals	mineral	NOUN	NNS	Number=Plur	4	nmod	4:nmod:of	_
7	there	there	ADV	RB	PronType=Dem	2	advmod	2:advmod	_
8	and	and	CCONJ	CC	_	11	cc	11:cc	_
9	you	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	11	nsubj	11:nsubj	_
10	can	can	AUX	MD	VerbForm=Fin	11	aux	11:aux	_
11	figure	figure	VERB	VB	VerbForm=Inf	2	conj	2:conj:and	_
12	out	out	ADP	RP	_	11	compound:prt	11:compound:prt	_
13	what	what	DET	WDT	PronType=Int	14	det	14:det	_
14	percentage	percentage	NOUN	NN	Number=Sing	21	nsubj	21:nsubj	_
15	of	of	ADP	IN	_	16	case	16:case	_
16	that	that	PRON	DT	Number=Sing|PronType=Dem	14	nmod	14:nmod:of	_
17	would	would	AUX	MD	VerbForm=Fin	21	aux	21:aux	_
18	be	be	AUX	VB	VerbForm=Inf	21	cop	21:cop	_
19	your	your	PRON	PRP$	Case=Gen|Person=2|Poss=Yes|PronType=Prs	21	nmod:poss	21:nmod:poss	_
20	hardness	hardness	NOUN	NN	Number=Sing	21	compound	21:compound	_
21	minerals	mineral	NOUN	NNS	Number=Plur	11	ccomp	11:ccomp	_
22	(	(	PUNCT	-LRB-	_	21	punct	21:punct	SpaceAfter=No
23	calcium	calcium	NOUN	NN	Number=Sing	21	appos	21:appos	SpaceAfter=No
24	,	,	PUNCT	,	_	25	punct	25:punct	_
25	magnesium	magnesium	NOUN	NN	Number=Sing	23	conj	21:appos|23:conj:and	_
26	and	and	CCONJ	CC	_	27	cc	27:cc	_
27	iron	iron	NOUN	NN	Number=Sing	23	conj	21:appos|23:conj:and	SpaceAfter=No
28	)	)	PUNCT	-RRB-	_	21	punct	21:punct	SpaceAfter=No
29	.	.	PUNCT	.	_	2	punct	2:punct	_
