Ive just brought an eheim classic off ebay, it doesnt come with any instructions or the usual accessories like long peices of hose. basicly ive tried to get it started in a bucket. ive siphoned the intake hose to get the water to fill the filter, i onl get a dribble out of the output hose if its level with the filter water level, otherwise i get nothing at all. any help why it isnt working? and its making a scraping noise when its on.