I have a fluval 203 on my 30 gallon and ever since the power failure it hasn't been working quite right. So I tried to fix it today and it seems to be working WORSE. Now it is making whirring noises and starts shaking. There's air bubbles coming out of my intake as well. Any ideas what it could be or how to fix it?? I think it has to do with the propellor but I don't want to mess with that!