salt and hash password problem

I am creating a one-way hashed password to store in my db. I am using a salt size of 5. When the password is created the salt value is 8 characters. See code below:

Dim saltSize As Integer = 5
Dim salt As String = CreateSalt(saltSize)
Dim passwordHash As String = CreatePasswordHash(trim(txtPassword.Text), trim(salt))

response.write("<br>salt value: " & salt)

Private Shared Function CreateSalt(ByVal size As Integer) As String
      
Dim rng As RNGCryptoServiceProvider = New RNGCryptoServiceProvider
Dim buff(size) As Byte

rng.GetBytes(buff)
Return Convert.ToBase64String(buff)

End Function

Private Shared Function CreatePasswordHash(ByVal pwd As String, ByVal salt As String) As String
      
Dim saltAndPwd As String = String.Concat(pwd, salt)
Dim hashedPwd As String  = FormsAuthentication.HashPasswordForStoringInConfigFile(saltAndPwd, "SHA1")
hashedPwd = String.Concat(hashedPwd, salt)

Return hashedPwd

End Function

However, when I try to authenticate a user that is trying to log in I am having a problem:

Dim dbPasswordHash As String = reader.GetString(0)
Dim saltSize As Integer = 5
Dim salt As String = dbPasswordHash.Substring(dbPasswordHash.Length - saltSize)

Dim pwdHash As String = CreatePasswordHash(txtPassword.Text, salt)
passwordMatch = pwdHash.Equals(dbPasswordHash)

The returned salt value is not of length 5 but it is 8 characters. The authentication thus fails ? can someone help with this query ?