Why do some spas come with a dial that sends pressure to different areas of the spa?

This is called zoned plumbing.  The manufacture takes a pump and sends all the power to one side of the spa or to different seating areas. So if your the only one in the spa you can enjoy all the power to one seat. Also look for MassageAir therapy valves, this adds soothing bubbles through all the jets.

Posted in: Hot Tubs and Spas