Unfortunately you can't just go by hp when replacing pumps. It is all about flow and 2 different 1hp pumps can have drastically different flow rates. Add on top of that the marketing baloney of the max-rated/up-rated energy efficient pump which is just remarking a pump at a higher hp than it really is.

So you'd need to compare the performance data for the old pump to the Hayward data at http://www.haywardnet.com/abovegroun...ctID=121#three to see which pump comes closest to matching.