Have an older inground pool with a Pentair cartridge filter and Hayward pump Power flow LX. Getting constant air in the basket and very low pressure. 2 to 3lbs max. Guess I'm looking for guidance as to where I should start. AT one time it did work well and remember close to 15lbs with this setup. Over the years it's become worse and now barely moves water. It does not hold prime for more then day. Thanks in adavnce!!!