Once I add an acid, such as lactic acid, the balance is thrown off and I might end up with a cation level of 6.9 meq/L and an anion measurement of 4.5. This leaves the cells yellow now (row 12 Finished Water Profile).
I guess this is a two part question, one about the use of the software itself and one about water chemistry for brewing. In the case of the software, do the cation/anion columns on the Water Adjustment sheet for the finished water profile mean anything in terms of the quality of the final water makeup or is it mainly for determining the validity of the original water report?
Secondary question that might need to be asked else where is if as a brewer, should I try to maintain a balance between cations and anions when making water adjustments to have a positive effect on the outcome of the beer.
Ah, now I see the dilemma. Greg, you are right. When you add an acid on the Water Adjustment sheet, the bicarbonate is neutralized by the Hydrogen proton into water and CO2. The problem is that for most of the acid choices listed in Bru'n Water, the acid anion is not added to the anion total when the hydrogen proton is added. That is where the "imbalance" is created on the sheet. That imbalance does not exist in reality since that acid's anion is added to the water. Since anions like lactate or phosphate aren't of much interest in our brewing, they weren't listed in the simplified cation and anion listing in Bru'n Water.
As an aside, if you select either sulfuric or hydrochloric acid as your acid on the Water Adjustment sheet, you will see that the cation/anion balance is maintained since Bru'n Water does calculate either the sulfate or chloride ion addition and includes that in the anion total.
Good catch on this pecularity of the program. I'll add a note in the program that adding acids may cause an imbalance, but its nothing to worry about.
Second question: No, the cation/anion balance is relatively meaningless on the Water Adjustment sheet since when adding any of the other minerals and SOME acids, the added cations always equal the added anions. If the original water was balanced reasonably, the finished water will also.
Secondary question: There is no easy way that you can add just a cation or anion to water. The ionic salts we use in brewing always are balanced. You will always add exactly the same number of milliequivalents of the cation as the anion.