Do I need to make another Bracha on putting on tzitzis after I get out of the pool?
The answer is, (I do not have the source) in all situations If, at the time that he took them off, you knew that you would be putting them back on, you do not have to repeat the bracha.
It is a machlokes Mechaber and Rema (8:14). The Mechaber says to make a new brocha, and the Rema says not to (see Mishnah Berurah 38). So, it would seem that a Sefardi should, and an Ashkenazi should not. There are more details, but this is the basic answer.