I have a cf700 which is a good filter
The one problem I have had with it was when it was on my discus tank at 30*C, the hoses went all soft and kinked really badly, to the point where there was actually no flow, and the tank had an ammonia spike and killed 2 discus.
It kinked just by the taps. I put a soft spring (from a sheep drench pack) around the hose and that fixed it
Just a warning