You would be doing yourself (and your pool!) a HUGE favor by getting and using your own test kit rather than relying on pool store testing. We highly recommend the K-2006 (link via Amazon can be found in mine and Watermom's sigs). It is an investment, but one that will pay for itself multiple times over during this swim season in less frustration, less green water time, and more swim time.

If you get it through the Amazon link, only buy it if Amato Industries is the seller--some of the other companies are substituting the K-2005, which is NOT the same thing.