When adding pickling lime to the mash, do you add this just like any other mineral addition? I am confused because on Bru'n Water it states that it raises the PH to 11 causing other minerals to fall out then you take the water physically off the minerals that fall out. At least that's how I read it.
Adding lime to the mash itself is advantageous in that you can do it as a means of adjusting the mash pH in the mash itself. IOW, if you find the mash pH is low, you add some Ca(OH)2, stir thoroughly, wait a couple of minutes and check pH again. If pH is still to low, add some more and repeat the process. Adding it to the mash is disadvantageous in that thorough mixing is difficult, especially in a thick mash, and time consuming. From this POV it is better to add it to the mash water. Whether this will result in precipitation depends on whether there is any bicarbonate in the water and how much you add. If the water contains bicarbonate in sufficient quantity and the pH goes high enough then you will drop calcium carbonate thus reducing the alkalinity, which is what you are striving to achieve by addition of the lime to begin with. But water with some alkalinity will resist pH increase because the bicarbonate provides buffering (resistance to pH change).
If the water contains magnesium and enough lime is added to raise the pH to 11 the magnesium will precipitate out as magnesium hydroxide. This is the first step in 'split treatment' softening of water an appreciable part of whose hardness is magnesium hardness. The magnesium will redissolve readily when the grist is added and the pH reduces to mash pH. That is not the case with precipitated calcium carbonate. That takes a long time to dissolve.
So if I add Calcium Chloride, is adding pickling lime just going to make the Calcium fall out of the solution then?
No, if you are making the additions to low ion (RO or DI) water as such water contains bicarbonate (nor magnesium).
It's probably worth noting that if you use lime to supply alkalinity you are deviating from 'natural' brewing as in natural brewing alkalinity is supplied exclusively by bicarbonate ion and the bicarbonate is usually paired with calcium and magnesium. To get calcium and magnesium bicarbonate into a synthetic water prepared from RO/DI involves the use of carbon dioxide gas in imitation of the way that nature gets these 'salts' into water. This can be done but one of a several elaborate, time consuming processes must be carried out at the completion of which, as soon as the water is placed in the HLT, the bicarbonate/carbonate often precipitates right back out. Water tends to naturally decarbonate itself in the brewing process which implies that if you have to add a lot of alkali to a mash you are probably using more dark malts than the brewers who created the style are likely to have used. OTOH as home brewers love to experiment that may be exactly what you have in mind.
Another thing worth noting is that lime is not as effective as the stoichimetry would suggest. This is because some of the dissociated hydroxyl ions are immediately neutralized by hydrogen ions released when the dissociated calcium ion reacts with malt phosphate. You can read more about this at
http://www.wetnewf.org/pdfs/chalk.html if you are interested.