Ussually it's better just to use a good Alk buffer and make sure the Calcium is balanced, as gsellers said.
PH Buffers are better for fish only systems, but in reefs they tend to add too much Borate, which over time can cause problems.
Kalkwasser can help, as well as vigirous water flow at the surface of the tank to improve oxygen exchange. If all else fails, opening a nearby window can help if it's in a stuffy area.