Since you say "there was no improvement" I assume the pump was still cycling on and off?
The principal of the Aquagenie and the CSV are the same. Although the bypass of the CSV is more dependable. Sounds like whoever installed it didn't know how to adjust it. It is not that hard but for some reason people will tighten on the bolt, which makes the valve work like a piece of pipe. Loosening on the bolt makes the valve work.
Plumbers and pump installers will try to sell you what they make the most money on, which is the variable speed pump by a long shot. They are expensive, short lived, and greatly shorten the life of the pump as well.
They can't make any money selling a $63 or a $200 CSV, especially because it will make the pump last 4 times longer than normal.