ReefRaf, I don't disagree with you but in general I hedge on the side of caution in my advise. You have a lot of rock and almost all SPS so you have the type of tank the Stream was particularly designed for. This type of advise is always difficult for me, as I am not looking at your tank, even a picture doesn't give the same feel as being their. I am not trying to misguide anybody but if you read the majority of threads most people feel a 6100 is too much for a 4ft aquarium, in general I think 2 6000 is the ideal solution with one pump on high while the other pump is on low, programmed through the multicontroller. I do not see anything wrong though with what you intend to do and it should be fine.