So I got the new magnet because mine was scored, but when I went to change it I noticed that the impeller was cracked. I would like to think that I would have noticed this before and that the crack was due to trying it repeatedly when it wasn't working, but who knows, I could have just been missing that important fact the whole time. I got the new impeller, installed everything today, and it works great. No fish died due to my shenanigans without my main filter running, and now it works so I am happy. Thanks for all of your advice.