Wet/dry

[carsten]

I was just curious about the recommended size of wet/dry filter that should be used with a 75G tank?

Carsten

[Discusgeo]

You will need one which measures only 20" x 10" x 12" (L x W x H). This filter should hold at least 4 gallons of bio-media capacity, enabling it to support saltwater aquariums up to 90 gallons.

Here is a link that may help you out.
George
http://www.wetdryfilter.com/