Just want to add the comment to be sure you are using the correct bleach product. Some people used Splashless bleach and killed off the fish in their aquariums!
From Seachem's website is the following:
The regeneration instructions are specific to using regular 8.25% hypochlorite household bleach (non scented, no dyes). From our research, the dilution of 4 tbsp of
Prime for each 1 cup of water volume will successfully neutralize the amount of 8.25% bleach used in the 1:1 ratio.
The directions on your package may say to use 2 tbsp of Prime. This was based on what used to be the most commonly sold household bleaches which were 6%. This concentration is not sold anymore.
By doubling the Prime dosage, we are accounting for newer 8.25% hypochlorite bleaches while erring heavily on the side of caution.
Also, we would not recommend using a splash-less bleach or a 33% more concentrated bleach as these will not be in the proper form or concentration for the regeneration process. We also recommend smelling Purigen® after the regeneration process. If there is a chlorine or bleach smell, repeat the process of soaking in Prime.