How long was the test sample sitting around before the LFS tested it? Can make a difference. For best results, keep the water in a cooler during transport. If you can, test your water from your tank with 2 different tests, and make sure they are both either broad range, or in the correct range for your water. Some test kits are high or low range. If you're using a low range kit, 7.2 might be the highest it can read, no matter what the water actually rates at. Before making any changes, make sure you are comfortable that you know the value of the water as it sits.
Also--sudden changes are bad, of any kind. Taking a fish from gross, goeey water and dropping it into a sparkling tank can cause shock as easily as the reverse. If your fish are alive and fine in your current water, there is no reason to change it unless you want them to breed. If you are looking to purchase more fish, then you'll need to acclimate them to the water--much easier than changing the tank.
Anona got it right--pH can be changed, but only carefully and with planning. The 'magic bullet' chemicals tend to cause problems other than bouncing pH, since they introduce nutrients for algae.
