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Lime softening

Ok, I know there are easier way to lower alkalinity but I like to experiment. that being said, here’s my question.
after I add lime to hard water and most of the hardness drops out I decant. other then added calcium and lower alkalinity, doses this water change in any other way . what I’m worried about is the ph of the lime softened water and any other negative affects. one thing I know is that this water will give me lower ph in my mash because there is less hardness after lime softening but what else may happen. I may be way off here but oh well.
Thanks for any advice.

Lime raises the pH.

In this case it raises pH then precipitates out thus reducing hardness and pH. I couldn’t find much additional info so it seems legit. Hopefully Martin will catch this thread and chime in.

First, understand that lime softening is most suited to water with high Temporary Hardness. It will not affect Permanent Hardness. If there is much sulfate or chloride in the water, the water probably has significant Permanent Hardness and the treatment may not provide much softening.

The lime raises the water pH to the point that the solubility of metals is significantly decreased. Most know that iron is a metal, but so are calcium and magnesium. Raising the water pH to 10 will get the calcium to drop, but the pH has to be raised to at least 11 to get the magnesium to drop out.

Although you are adding a bunch of calcium with the lime (calcium hydroxide), that calcium precipitates out as does most of the other calcium in the water. So the calcium content does go down with the lime treatment.

This treatment also shows that pH and alkalinity are NOT the same thing, nor are they well related. So you are dosing the water with lime and the pH is increased. But the precipitation of the calcium as calcium carbonate also takes out the carbonate and bicarbonate that create alkalinity in the water. Yes, the pH of the lime treated water is high. But the alkalinity has been substantially reduced in water with high Temporary Hardness.

Lime treated water DOES need to be pH adjusted to make it more usable for drinking or brewing. The common initial treatment is to run the water through an air-stripping tower so that carbon dioxide can be infused into the water to create carbonic acid and reduce the pH a bit. Since a homebrewer probably doesn’t have an air-stripping tower, another choice is to bubble air through the water for hours. All that air treatment cannot bring the typical water pH down to usable level, so an external acid is typically added. Sulfuric or hydrochloric acids are often used in commercial and municipal systems. Homebrewers can use any typical brewing acid too.

With an ideal water with very high Temp Hardness, you can knock a lot of calcium, magnesium, and alkalinity out of water and be left with calcium under 20 ppm and bicarbonate under 60 ppm.

thanks for all the info mabrungard. it was just what I was looking for.

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