Should I use Alum to get rid of silt and mud

The pool store recommended Alum to get rid of silt and mud. Any down side to using Alum or clarifier? thanks
Amir

I've used clarifier in the past and it didnt do anything. From what I've read you need a LOT of it to make a difference....and even then it can cause other problems.

I'll never put clarifier in my pool again but thats just my opinion.