you might want to look at tunzes. you can direct them and its controllable if you get the controllable models. they are linkable but you have to buy a separate controller. i was going to get these but i got the vortech mp10 at such a good price so i decided on the vortechs
Turbelle® nanostream 6055: (6055.000) ~$230
* For aquariums from 40 to 500 litres (11 to 132 USgal.)
* Flow rate: 1,000 to 5,500 l/h (264 to 1,453 USgal./h)
* Energy consumption: 4 - 18 W
* Voltage / frequency: 230V/50-60Hz
* Cable length: 5 m (196.8 in.)
* Dimensions: diam. 70 mm (2.7 in.), output: diam. 40/15 mm (1.5 / .59 in.)
* Turbelle® stream 6105 ~$330
* For aquariums from 200 to 2,000 litres (52 to 528 USgal.).
* Flow rate: 3,000 to 13,000 l/h (792 to 3,434 USgal./h).
* Energy consumption: max. 45 W.
* Voltage / frequency: 100 – 240 V / 50 – 60 Hz.
* Cable length: 5 m (196.8 in.).
* Dimensions: diam. 90 mm (3.5 in.), Outlet: diam. 50 mm (1.96 in.).
* Magnet Holder up to a glass thickness of 19 mm (.74 in.).