I cant claim any special knowledge on this but the problem does seem to be the flow through the filter and not the flow into it. The previous owner may have been using a larger pump than you but as he was pump feeding the filter i.e from the bottom of his pond it may not have been as efficient as yours pumping the other way. It would have to overcome the head and any pipework restrictions there may have been.
Posted on Oct 27, 2005, 3:01 PM from IP address 82.138.200.101