I own two Mag Drives (a 7 and a 36) and they both stink. I use the Mag 7 to mix SW in a large trash can because it also heats the water to about 80 degrees on its own.
I've had SOOOOO many problems with the mag drives and don't recommend them. On the other hand, since I bought my blueline, I've been thrilled with it. My Mag 36 is in it's box on a shelf in case of an extreme emergency (and it would have to be extreme).
Danner has been decent (but slow) as they replaced the impeller on my 7 twice (and redesigned it because of the number of problems), and the impeller once on my 36 and the entire 36 once since it siezed up.
Just thought I would throw this out. You could probably search this site for mag drive and see all of my problems as they were occuring.