Several Return pumps allow external 0-10v flow adjustments. These types of pumps can very easily be controller through the ProfiLux and it's available 0-10v L ports (Yellow) To get started, you need to have either: GHL compatible 0-10v cable for your pump. OR GHL LBF-AP module - Connects to L port and provides terminal pinout for connecting bare wires (-/+) 0-10v signal With this we can set the speed/flow of the pump, throttle it down at night time, increase for thunderstorm and/or decrease for feedings. In my example, we're going to set the return pump for consistent flow - no wave motion or increase/decrease during normal use. It's all in the Stream Group setting. In my case, I use Streamgroup 8, I added my RD3 10v interface on L3 to the group, and set it: Mode: Permanent Waves: no waves * Add Pump#: 3 We will set the running power to 60%, 25% during Feed Cycle, and 100% for wild flow during thunderstorms. Edit pump 3 for: Minimum: 25 Maximum: 60 (running power) Night: 40 Thunderstorm: 100 Behavior for feed: minimum Please let me know if you have questions or need assistance with building a program for you.