It seems like various versions of what you are describing have been done by more than one company. I may be misunderstanding though. In any case, you might have a slightly better approach or some advantage.

Lori, any water testing lab should be able to test before filtering and after filtering water samples to evaluate the effectiveness of the system. Such tests should run less than $100, may be even less than $50 each. Discuss with the lab your objectives and they can help you select the right tests. Look in the yellow pages under "water testing" or "environmental labs".