So I finally got the COR installed.
Went very well.
The Task setup made it super easy.
There is a calibration you do so that you can tune the pump to your tank.
1st step is to start the pump then turn it up or down till you get the flow you want. I ended up at 75%. The task then makes this your 100%.
The next step is the coolest.
You then tune the minimum flow. What this means is you adjust the pump till it pumps just enough water that the return plumbing doesn't drain. Ideally, it doesn't drain or put more water in that tank. I ended up at 16%. This is now your 0%.
So when I go in to Feed mode, water drains from the overflow but the return doesn't siphon!
Noise wise, it is very very quiet! If I put my ear into the return chamber and turn off everything else and I strain, I can hear it, but just barely.
I like it a lot!