cfs 700 help

Hi I have a cfs 700 that has really been issue free since I purchased it last year. My problem is I recently went to change the uv light on it and the nut that holds the wire in place that is submersed was cracked. I think this caused water to leak in and blow my light. I can only find a replacement for the entire pump assembly to replace this. Was wondering if anyone has come across this problem and if there is a cheap easy fix for it or am I going to have to bite the bullet and spend the $40 on a whole new pump assembly. Also, if this is the case am I better off spending the money on a inline uv sterilizer instead of replacing all this? Thanks for the input.