Fkshiu,
I am running a 9020 on my 150g. Total water volume is about 134 gallons with the sump (All Glass Model IV) after I subtract the water displacement of the live rock (200+ lbs), sand bed (2"), 1" difference from the water line in the tank to the top of the tank and equipment in sump. This is as best as I can figure. All said I have experimented running just one of the 9010's and it has been able to keep up easily. I have a fairly heavy bioload. Hope this helps.