Retrofitting a variable-frequency drive to my pool pump, regulating the speed, and saving electricity in the process—that’s exactly what I did with my SPECK BADU Magic II 8. With the AquaForte Vario+ II, the daily energy consumption of the pump and UV-C lamp dropped by about 43 percent, and at the same time, the system became significantly quieter. I’ll show you how I installed, connected, and configured the variable-frequency drive, what the measured values were, and why the lowest speed wasn’t the best choice in the practical test. I’ll also cover operating times, costs, and the requirements for a suitable retrofit.