RO Water + Tap Water = Dumb Question

[barneey]

Maybe a dumb question but here goes,

My water report is 238 Alkalinity, 184 Hardness, 65 Calcium, 5 Mg, 31 Na, 143 Co3, 23 SO4, 51Cl

If did a 50% / 50% split with RO water can I just half ALL the above figures

Cheers

C

[simple one]

Yes if it is commercially bought RO water.

If it is home RO system, which can be less than perfect, there may be a few more minerals than 50%.

[barneey]

Cheers for the reply, I`ve been trying a few experiements in Grahams Calc. to see if there was a tap water / RO water combination sweet spot. (Yet to find one) I`m also assuming the same applies with other mixing ratios 1/4 or 3/4s

Regards

[simple one]

Is your alkalinity expressed in CaCO3?

I think your on the right lines. 3/4 tap water or no dilution for stout and porter, 1/5 for pale ales, with the obligatory teaspoon of gypsum or calcium chloride in mash and boil.
It's the opposite of what I do. I have to add mineral rich bottled water to my soft tap water to brew anything dark, with a touch for the ruby beers.

A good way of checking your ratios are correct is by using an alkalinity test kit once it's all mixed. Then I usually take the final pH of the beer and assess the taste and mouthfeel, and then alter my dilutions for the next beer. It's all for your taste.

[barneey]

Yep the full report is this

pH 7.43
Alkalinity as CaCO3 238.00
Carbonates as CO3 142.80
Nitrate 29.60
Chloride as Cl 51.40
Sulphate as SO4 22.63
Total Hardness 184.00
Calcium as Ca 64.80
Magnesium as Mg 5.28

Interestingly I also have another report taken at the same time, test being carried out by another person (never did get why the 2 reports were different tho?)

Mg 4.7
Ca 123.0
Mn 0.0
K 2.9
Na 31.4
NH3 0.0
SO4 22.8
NO3 37.6
Cl 54.7
F 0.1
PO4 0.0
Alkalinity (CaCO3) 242.0
Hardness (CaCO3) 326.48

Cheers