so confused by water report

anybody?

runningweird said:

the problem, as I saw it, was that there wasn't enough straight calcium in the water to start with to complete the reaction, so I was ending up with some left over lime in the water.

Click to expand...

Calcium, Ca 104 = 5.2 mEq/L
Total Alkalinity, CaCO3 335 = 6.7 mEq/L
so you are 1.5 mEq/L shy on the calcium. Make that up and you ought to be able to drop both alkalinity and calcium hardness to about 1 mEq/L each.

Lime softening is a bit tricky as you never know exactly what you are going to get. You really need a pH meter to monitor what is going on (though I guess strips would be good enough here). You calculate how much lime you need From Ca++ + 2HCO3- + Ca(OH)2 --> 2CaCO3 + 2H2O its pretty clear that you need 1/2 mmol of lime for each 2 mEq of bicarbonate removed. Add this amount to half the volume of water to be treated and stir. The pH will initially be high but as the chalk precipitates (add a bit before you start to serve as nucleation sites) the pH will fall back some. When it stabilizes add more of the water and monitor pH until you reach about 8. Stop there. Let things settle and decant. It is really a good idea to do alkalinity and hardness checks on the decanted water to see how well you did.

Thanks! should I just add straight calcium? or gypsum

In the first place, you would probably have difficulty obtaining calcium. In the second place, if you add it to water you get

Ca + 2H2O --> Ca++ + H2 + 2(OH)-

which is, after the hydrogen has left, the same as adding Ca(OH)2. So use gypsum or calcium chloride to increase calcium ion content.

ajdelange said:

In the first place, you would probably have difficulty obtaining calcium.

Click to expand...

Ha, I actually have an old container of pure calcium metal in my garage that has long since oxidized to now almost entierly CaO. I'd never thought of it, but maybe now i'll use if for beer...