I believe that if you look at
Water Filters for their 20-BB-34 housing ($72) and the Pentek CBC20-BB filter ($78), that you might like what you find. For my 8000g pond a 10% continuous flow is only .555 gpm. My research tells me that even though this filter is rated at 4 gpm and 100000gallons life, that chlorine removal is directly related to flow rate. This means that if you stay under 1 gpm then not only will it remove most chlorine, but also reduce the chlorimines as well.
I got this information after I called the tech guy at Pentek. The brochures can be misleading and confusing.
bruce