By the way, I was able to run the 12v pump with a standard 9v battery and the 6v one from a usb port.
The 12v one did make a different sound with the 9v supply, so it was obviously not operating as fast as with the 12v supply. I did not notice any difference in the 6v pump when connected to the 5v supply (USB).
I ordered two of each, they came in one box, and I can't tell which is which
Does the larger (12v) pumps seem plenty capable for doing a single tiered brew system? I'm mainly looking for something to pump hot water from the brew kettle to the mash tun, then pump the wort back to the brew kettle. Think this one could handle it?