SeedFinders Mini:Board

Please, write on the user account creation page which types of characters are allowed in the password. I tried numerous times to insert a secure password, and always got the error that some or other character is not allowed.
Also I had to fill out a captcha on every attempt. Wouldn't it be enough to check that I am a human once?
Also there seems to be a problem with umlauts, the first time the account creation worked I could not log in with the password that seedfinder displayed after the account creation, so I had to select another username and do it all over again.