I need new filter to replace the old and blown out DE filter I currently have. It is tired and blows back DE into the pool. The IG pool is currently a pond, full of algae and mud 
, due to the heavy rains and poor yard drainage. I want to replace the old DE filter with a cartridge filter but need to know what size. The pool is sort of a circle and has a waterfall spa feature. By my estimate the pool and spa volume is about 8353 gallons (18 ft x12 ft, so I used (pi r2) for area with a radius of 9ft, average depth of 4.0 ft =7610 gallons ) . The Spa is about 6.5 ft in diameter and 3 ft deep so (3.14 x 3.25 x 3.25 x 3 x 7.48 = 744 gallons. The pump is a 2 year old pentair wfe-4 11 hp single speed with a max gpm of 120. I am looking at the Hayward Star Clear C900 90 sf with 2 in plumbing. Will this combo work out ok ? And is the 90 sf cartrige filter bigg enough for my pool set up?
, due to the heavy rains and poor yard drainage. I want to replace the old DE filter with a cartridge filter but need to know what size. The pool is sort of a circle and has a waterfall spa feature. By my estimate the pool and spa volume is about 8353 gallons (18 ft x12 ft, so I used (pi r2) for area with a radius of 9ft, average depth of 4.0 ft =7610 gallons ) . The Spa is about 6.5 ft in diameter and 3 ft deep so (3.14 x 3.25 x 3.25 x 3 x 7.48 = 744 gallons. The pump is a 2 year old pentair wfe-4 11 hp single speed with a max gpm of 120. I am looking at the Hayward Star Clear C900 90 sf with 2 in plumbing. Will this combo work out ok ? And is the 90 sf cartrige filter bigg enough for my pool set up?