I want to use a strong authentication scheme, so I decided to use PBKDF2. I'm using PBKDF2 with SHA256 algorithm, 5000 iterations and I use username (which is full email address of user) as salt. So every user have a unique email, their email address is their identifier. So when they enter password, I'll use PBKDF2 with 5000 iteration and SHA256 algorithm to hash user's password.
Do you think it's good? Can you tell me if there is any security weakness on this hashing scheme?