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Ales

New Member
I recently started using EZ Water Calculator to try to estimate my mash pH. However, in the Sulfate column, it states:

"If your water report gives Sulfate as Sulfur (SO4-S) such as a Ward Lab's report, multiply by that by 3 to get SO4"

I indeed do have my water tested from Ward, and they do give the PPM Sulfate as SO4-S. However, my PPM SO4-S is 335. This is already high, and it is 1005 PPM if I multiply it by 3! That got me thinking, are my sulfates really that high or is EZ Water's recommendation to multiply it by 3 off base?

Thanks for any insights

Yooper

Ale's What Cures You!
Staff member
Mod
Yes, that is the recommendation on bru'nwater too.

The reason is the way Ward lab reports S04. SO4-S is "sulfate as sulfur", and not "sulfate". Since it's "sulfate as sulfur", to get the sulfate, you need to multiply by 3.

ajdelange

Well-Known Member
It's not really a recommendation, it is something you must do in order to convert sulfate 'as sulfur' to sulfate 'as sulfate'. What sulfate 'as sulfur' means is the amount of sulfur in the sulfate in your water. Keep in mind that Wards primarily serves the agriculture industry where the amount of sulfur applied per acre, the amount of nitrogen applied per acre (Ward reports NO3 - N i.e. 'as Nitrogen') etc. are what is of interest. So if your water contains 335 mg/L as sulfur that means that the sulfur content of the sulfate in your water is 335 mg/L. The molecular weight of sulfur is 32.06 so that 335 mg of sulfur is 335/32.06 mmol. There is 1 mmol of sulfur in each mmol of sulfate so you have 335/32.06 mmol of sulfate as well but the molecular weight of sulfate is 96.079 mg/mmol so the weight of the sulfate is 335*(96.079/32.06) = 335*2.99685 = 1003.94 mg. We generally consider 3 as being close enough to 2.99685 for practical work and it's certainly easier to remember.

I well remember when this finally dawned on me as I just couldn't figure out why I could never get the same cation concentrations as indicated on the Ward Labs reports. I'd been staring at one for what seemed like hours and finally I saw that '-S'. It was a real Homer Simpson 'doh' moment.

Now as to the actual numbers: do you live near a gypsum mine or sulfuric acid factory or a battery manufacturer or something like that?

OP
A

Ales

New Member
Both of these replies were extremely helpful. The time you didn't need to take, but did, to help a fledgling like me is much appreciated.

As for the sulfate levels... I have no idea haha yuck. Diarrhea is supposed to set in at sulfate levels above 400 ppm, but I've had no problems so I don't know what could be going on