Username and password login form

On one of our sites we have a made a GravityForm that is used to send people to another site after they have filled their username and password. The form works great, but I see a disturbing big number of records being created in the DB, and this has now become such a big problem, that we will have to change to another solution if we can't get this solved.

The thing is - we have no need to save any records of what people fill in this form in the db. We just need to redirect them to the other site with username and password already filled.

Is there any way we can be able to stop recording fill ins of this form, so we avoid having to leave Gravity Forms as solution and start looking elsewhere?

This can work as soon as we are not running the site in Wordpress MU anymore. Right now it's in a MU environment, so it would affect several sites.

Thanks for the tip though. I will test it when we are done splitting up the sites in to separate installs.