Do You think that Tunze Trubelle Stream 6000 (output: 2500 - 7000 l/h, 660.4 - 1,849.2 US gal/h) will be to weak (a tank turnover rate of 3,6 - 10,0 times an hour)?
The 6100 will be fine and with the water speed adjustment on it, you should be able to set the pump to suit your tank.
Thanks ...