humming sound in impeller

Question
I have an external filter for about one year now. And yesterday I was cleaning the intake pipe. When I switched back my filter on it wasn't working. Finally it has started working but now it has developed a loud humming sound. I have tried reinserting the intake pipe and the strainer to the powerhead many times but my tank is still making the hummmmm sound. Im scared the vibration is stressing out my fish.

Answer
This is not really my area of expertise - when it comes to the filters I usually have someone else put them together for me. Some are very simple, such as the under gravel filters, and others are fairly complicated, such as most canister filters. I do know that a constant loud vibration will be most stressful to some fish, especially the more delicate ones (such as smaller, thinner skinned tetras, and African dwarf frogs who can actually die from loud vibrations). My recommendation would be to either take it to a pet store and find some one in pet care who knows what they're doing and have them put it together for you so it won't hum like that, or they may tell you to buy a new one. Or - look up the website for that specific brand of filters and see if they have any online manuals for you to read. If you think it's hard to figure it out in person - it's much harder to help someone over the internet - though we may have an expert or two who knows filters inside and out. Thank you for your patience with me, and I hope you are able to make some use of the options I gave you.