just go with the manufactures recommended size vortech per your tank size.
[TABLE="width: 85"]
[TR]
[TD]Model
[/TD]
[TD="colspan: 2"]Flow Rate (gph)
[/TD]
[TD="colspan: 2"]Watts
[/TD]
[TD]Dimensions
[/TD]
[TD]Aquarium Size
[/TD]
[/TR]
[TR]
[TD]Min
[/TD]
[TD]Max
[/TD]
[TD]Min
[/TD]
[TD]Max
[/TD]
[/TR]
[TR]
[TD]MP10ES
[/TD]
[TD]200
[/TD]
[TD]1,575
[/TD]
[TD]8
[/TD]
[TD]18
[/TD]
[TD]2.5" dia x 1.5" high
[/TD]
[TD]up to 50 gallons
[/TD]
[/TR]
[TR]
[TD]MP10w ES
[/TD]
[TD]200
[/TD]
[TD]1,575
[/TD]
[TD]8
[/TD]
[TD]18
[/TD]
[TD]2.5" dia x 5" high
[/TD]
[TD]up to 50 gallons
[/TD]
[/TR]
[TR]
[TD]MP40w ES
[/TD]
[TD]1,000
[/TD]
[TD]3,200
[/TD]
[TD]9
[/TD]
[TD]28
[/TD]
[TD]3" dia x 5" high
[/TD]
[TD]50-500+ gallons
[/TD]
[/TR]
[TR]
[TD]MP60w ES
[/TD]
[TD]3,500
[/TD]
[TD]7,500
[/TD]
[TD]10
[/TD]
[TD]60
[/TD]
[TD]4" dia x 3" high
[/TD]
[TD]120-1,000+ gallons
[/TD]
[/TR]
[/TABLE]