My aquarium power filter turns on but does not actually work?

This could be because of many problems. I will name a few for you. First many filters need to be manually started, to do this make sure the filter is running then pour some water into the actual filter which may start the filter. Next, perhaps you have not put the sucking propeller into the filter which would result in no water flow. Third, lots of times people do not put the filter bag in correctly or if you have a bio-wheel sometimes it is not set into the notches right. If you are still having trouble you can always ask the dealer of the filter or a local fish or pet store that sells filters.