See image below once the seal is removed you will need to clean the bottom of the shower door as hard water buildup is most likely on the bottom of the shower door.
Replace seal bottom of shower door.
When replacing the shower door bottom seal you will need to fully open the shower door to access the seal.
Carefully remove the old seal from the door by sliding the seal downward.
Remove the old sweep or seal clean the glass edge of the door use a glass safe scraper to remove any dirt or residue and clean with your favorite glass cleaner and a soft cloth.
The seal should be tight and take some effort to get seated correctly.
Install the seal onto the door by pressing one end of the seal onto the corner or end of the door and then pushing the seal into place from this end working your way to the opposite end.
Inspect the bottom of the shower door to determine the plastic seal attachment method.
Seals typically slide into a channel at the bottom of the door or they are placed between the base of the door.
Replacing shower door bottom seal is very easy.