Does anyone have any ideas as to why there is not just a general purpose control solution for glucose meters. I know that there are control ranges, but why does each company say you must use their control solution? If you have a premium brand named meter, the control solution can cost as much a $10 per bottle. The first ingredient on every bottle that I have used is water and the second is d-glucose. I think it is just a way for a company to make extra money.