You can move your pH down with Muriatic Acid. See the link in Watermom's sig above for handling Muriatic Acid. This will also lower TA.
Ben recommended that you bring you pH to the lowest on your tester. This is to help with the scaling.
The process for lowering tA is to add Muriatic acid, this lowers pH and TA, then areate the pool, this will raise pH without raising TA. Repeat this process when the pH gets up to 7.6 (maybe 7.4 in your case) until you have your TA at the level you want.