Thanks for the response. The reason I'm asking is because I've always preferred the Stainless Steel filters. For some reason about 10 years ago, all of the pool service companies seemed to have replaced the stainless steel Nautilus with the FNS filters. I never understood why? ... It almost seemed like thievery. Anyway, I've been looking for a used Nautilus NS filter and finally found one for a reasonable price. According to the manual the NS36 will filter 43,200 gallons in 10 hours, where my current FNS filter does 43,200 in 8 hours. I was thinking just run the pump longer and I would be good. Before starting to type this response I learned that the used Nautilus NS 36 has a few tears in the grid system, so I think I'm going to pass on it anyway. I agree that the NS48 would be ideal. Thanks for the response.

- I would estimate the pump to be between 18" - 24" above the pool waterline.
- Pipe diameter is 2"
- Suction Pipes (I have two skimmers and a main drain feeding water to the filter system). I would estimate them to be an average of 20FT.
- I currently do not have a two speed pump, but filter pressure is usually between 18 - 20 PSI
- No heater