MJ1200 with a white prop from the Sure Flow kit yields about 2000 gph. Though I have found using the 900's gives the best results. The white prop on the 1200 more often than not tends to make noise even though the white prop was suppose to resolve the problem.
koralias for the money are great, i switched over to a tunze nanostream 6025 though and the flow is better with a smaller footprint. you pay for it with price though, as i payed $80 locally plus tax, online they go for $70. Im giving a vortech hard consideration but right now im a lot more interested in finding a lighting fixture.