40 breeder. A gyre XF350 on each end (about 10.5k gph max flow volume combined), and a tunze 6040 (1200 gph each) on the backwall about 1/3 of the way in on each side, facing front.
You don't want water velocity (which is what changing the "nozzle" of the return pump gives). You want water volume. Especially in smaller tanks where you don't have the luxury of placing corals inches to feet away from powerheads to negate the velocity of water coming from them. It's imperative to use powerheads with as wide an output as possible, hence my use of the gyres. The 6040's are great at this, too, since they have a deflector which greatly reduces velocity and disperses the flow out over a greater area.
(FWIW, I find the vortech's output to be much too focused to optimize usable display area in small tanks).
Although I only run the gyres at 60% max, with my setup I'm well over 100x turnover yet nothing is being blasted by high velocity water. The practical result of this is that I have coral within 3 inches of powerheads and there's no tissue damage. And that volume of water still pales in comparison to nature. I don't just have SPS -- I've got a frogspawn (went from 1 to 7 heads in a year), duncans, and an alveopora that are all thriving.
To be clear -- placing a nozzle isn't going to increase the amount of water being moved. On the contrary, it's going to sacrifice flow volume for flow velocity when, what we REALLY want to do, is maximize the amount of water moving past a point to both provide a fresh "batch" of elements and nutrients to be accessible and to allow for coral waste products to be removed from the "microclimate" around the coral.
