The question is , why do you need users to register to use your website? it is silly. notice that you are not providing the users with ability to post or upload things to your website, therefore you should not worry about registrations.
the service you are providing is something close to whattomine ,coinwarz or anything mining-calculation related, you do not expect us to login to use such a service.
i am not accusing you for anything here, but just a word of advice, if you want to generate some profit, put some ads on the webiste. and let everybody use it without the need of registration.
edit: my bad, yes you do allow people to provide data, but still really not a good enough reason for registration. people don't get to make money posting fake results, neither registration ensure the integrity of the information they provide. thus i still think it's unnecessary.
appreciate the efforts tho.