First, you should know that a pH shift from 7.2 to 8.5 is not at all unusual in drinking water within a water system. It is not even unusual for water in an open pond measured over a 24 hr period. Second, the pH changes you are seeing is definitely not due to your pipes. In most water systems, pH is controlled (buffered) by the equilibrium between dissolved carbon dioxide and bicarbonate and carbonate ions. The carbonate and bicarbonate concentrations are affected by calcium carbonate (hard water scale is basically limestone) deposited in the system. As water gets more acidic, hard water scale dissolves. As the pH gets higher, more scale forms. Let me hazard a guess that your water source is groundwater. Groundwater typically has relatively high concentrations of dissolved carbon dioxide and relatively low oxygen concentrations because it is not equilibrated with the levels in the air. Some artesian wells even fizz like soda pop when the water reaches the surface. Aeration of groundwater within the system tends to release the carbon dioxide and increase the oxygenation and the pH by equilibration with the air. So the behavior you are seeing in your system is fairly typical for water of moderate alkalinity and moderate hardness from a groundwater source and sampled at aerated taps.

Validation of the char(1) type will need to be performed (duplicated) in every tier of the application to make sure the app can make a boolean decision based on it. It needs to be Y, N and not null in every case. In my view, this is "harder" than using a boolean-compatible bit type as the database representation. Would you choose to put all your dates and numeric values in the database as char(n) fields? "The" application can only be a GUI for the database if two conditions exist. One is that all of the business logic exists only in the database. The other is that the application be the only app that uses the database. Business logic doesn't belong in your GUI. And T-SQL is not the most flexible tool around for handling business logic. But feel free to do whatever blows your skirt up. It's all ultimately bit values, no matter how you code it. Tim Bailey Energy Laboratories, Inc.

By far the best argument is that it will make the business logic harder to implement. The database is storage for the application, not a pretty picture for the dba to look at. Maybe you can get him to accept views that show bit fields as Y/N. While you are at it, get him an Etch-A-Sketch and tell him it's a new Vista tablet PC. That will keep him out of your hair for a while.:laugh:. Tim Bailey Energy Laboratories, Inc.