Hi all, I'm busy trying to calculate the size of the surface area required for my vertical AS for a sea water setup. At the moment I have a 1600 litre tank (that's about 408 US gallons) If I understand SantaMonica and his formula correctly that means I need a 1.3meter squared (2015 square inches) double sided surface area? Seems so big. For a tank half that size they are running a much smaller unit (see http://www.youtube.com/watch?v=wD6kA3xDPaM ) it manages very well. I would struggle to fit the larger unit under my tank. Please tell me I've miscalculated or something. Busy Designing