What Size Pump And Filter

Need help in finding the right size pump and filter for my 18 x33 oval AG Pool.It game with a Jacuzzi 1.0 HP 2 Spd pump,and a Swimpro sand filter.The rate of the filter is 25 GPM/FT and the filter and backwash is 47 GPM,Holds 100 LBS of sand.The guy that installed the pool said I need a bigger sand filter that hold 200 lbs.said it would filter better for the size of the pump.Please can someone help me understand what the man is saying
thanks
Belinda

Personally, I am going to be using the pump and filter recommended on this page of www.poolsolutions.com. Specifically, this paragraph:

A combination that will work fairly well for almost ALL above ground pools -- regardless of pool size -- is a 1/2 HP Hayward "Super" pump (mfg. model #SP2600X5), a 22" Hayward "PRO" sand filter (mfg. model #SP220T), a Hayward 1.5" "Vari-Flo" multiport valve (mfg. model #SP071113), and a cord set (#SPX1550WA [25 ft long] or #SPX1250 [6 ft long]). 1999 list price on this combo is $764.00. Any pool dealer in the US or Canada can sell this combination to you. You'll also need hoses, connectors and . . . 250 pounds of filter sand. Make absolutely certain that the sand comes in bags that are factory labeled as filter sand, and make sure that the pump and filter have exactly the model numbers shown above. This combination can be used either as original equipment, or to replace what you've got now.