Bias is more than your gut feeling that the judge is favoring the other party. You have to show specific examples, such as giving one party more time or making disparaging comments about one of the parties.
Take notes of times you think the judge is showing favoritism so you can include them in your request.
Asking the judge to leave because you think they're biased doesn't always work. But once you make the request it becomes part of the record. On appeal you can bring it up again and maybe have another judge look it over. If nothing else, it gives you a reason to appeal.
