Agreed on the reverse mode. I could only detect minimal flow on reverse, I can't see how the impeller/rotor design on these pumps (or the original Maxspect version) could actually generate much flow in reverse. The paddle like design of the "ruggedised" version of maxspect blades looks like it would handle reverse flow a little better.
Interesting findings on the flow Metsin16, do you think yours are working ok? I have mine on 30% as of this morning in a four footer just to see if the sandbed and frags will take the flow. It does build momentum within the tank. In my case I left them overnight after setting them and woke up to carnage. I currently have mine set on W3 (reef/wave) mode to limit the effect.
I'm glad I'm not the only one struggling to strip them down, I was beginning to think I was just inept.

When I get a moment I will have a closer look at the rotors and cages as I can't work out how to get the end caps off to free the rotor from the cage.
Chris, Two of them in a 4x2x2 seems to be too much at anything over 20% on a constant flow or 30% (pending testing today) in wave mode, so 3 in a 2x2 would be way OTT IMHO.
Both seem to have been working flawlessly since we went away a week ago. Some of the SPS which hadn't fully extended their polyps prior to the cross flows going in were in full display when I got back last night which is great.
I'll continue testing and try a strip down at some point to see how gunked up they get.