Just got two DD-CPX1's
QUIETEST PUMPS I've tried.
1. DD-CPX1 ~ Eheim 1048 (it's been a while since I had the Eheim, but it was freaking quiet when mounted and bled properly)
2. Laing D5 @ 1
3. Laing DDC2 @ ~10V (on Sunbeam Rheobus)
Eheim 1046 is quieter than the 1048 (by a lot)
Eheim/Innovatek HPPS is quieter than the 1046 (by a little).
Also, the HPPS outperforms the 1046 by a bit, expect nearly
the temps you'd get with a 1048.
Yes, it's low-powered. So are the fans we all use. With a non-restrictive loop, it's all you need. Focus on radiator rather than pump.
Also, like all Eheims I've used, it vibrates, and needs to be isolated.