Math question!

[CoFlyGuy]

My water report for Aurora, give numbers for Hardness (as CaCO3) at 126. And Hardness-CA (as CaCO3) at 100. They also include Calcium at 4o. They do not include Magnesium MG. My question to you all is. How do I find the magnesium level from the numbers above?

Thanks in advance, I am more curious to learn the math than to really worry about currently tweaking my water.

 

[Herm brews]

I don’t have an answer for you, but I think this is kind of cool, even though it disregards one of the major water components of interest to brewers. Taken from the Aurora, CO annual water quality report:
Beer brewers and fish tank owners often need more information about our water than the EPA requires us to report, some of which is included below.

I bet if you asked, someone in the water dept. could probably give you an answer.

 

[Megary]

@Silver_Is_Money

I'd bet Silver would know.

 

[Donoroto]

My water report for Aurora, give numbers for Hardness (as CaCO3) at 126. And Hardness-CA (as CaCO3) at 100. They also include Calcium at 4o. They do not include Magnesium MG. My question to you all is. How do I find the magnesium level from the numbers above?

Thanks in advance, I am more curious to learn the math than to really worry about currently tweaking my water.

Magnesium needs to be measured separately. Your LHBS or @Nosybear might know, as likely would the water company folks if you ask politely.

126 is not super hard, so that's good. Ca of 40 is good, real good in fact - not too much, bit neither too little. If you're asking, find out about Chloride and Sulphate too, they are also important brewing 'salts'.

 

[Minbari]

You don't Mg is not listed there and is it's own element. You would have to test for it

 

[GFHomebrew]

Yup it should be in any decent water report if not I wouldn't trust it...

 

[Sunfire96]

Yep @Nosybear to the rescue

 

[CoFlyGuy]

Update: I went to my LHBS, The Brew Hut, and asked the guys over there about this question. One of the Helpful Brewer Staff members told me that he has been running his brews at an estimated 10 PPM for MG+. He doesn't exactly remember where he got the number but he said it had bounced between 8 and 10 the last few years. So, at this time I am running with 10 as a base number. I could probably get away with going with 9 as a happy medium.

 

[Donoroto]

Update: I went to my LHBS, The Brew Hut, and asked the guys over there about this question. One of the Helpful Brewer Staff members told me that he has been running his brews at an estimated 10 PPM for MG+. He doesn't exactly remember where he got the number but he said it had bounced between 8 and 10 the last few years. So, at this time I am running with 10 as a base number. I could probably get away with going with 9 as a happy medium.

Trust me, there is no perceptible difference between 8 and 10 parts per million of Magnesium.

 

[CoFlyGuy]

Trust me, there is no perceptible difference between 8 and 10 parts per million of Magnesium.

That was pretty much my feeling as well. So I have updated my Water Calc to this and should be pretty much ready to go.

 

[Nosybear]

Here's the formula:
Hardness = Cal * 2.497 + Mg * 4.118
where Cal and Mg are amounts of calcium (Ca2+) and magnesium (Mg2+) in mg/L, respectively.
Mg/l and PPM are equivalent.
Mg++=(hardness-(Ca++ * 2.497))/4.118
I use 6 ppm, if the guys at the Brew Hut use 10, it doesn't make that much of a difference.