More than likely this is what you need:
http://pondmaster-usa.com/Replacement-Diaphragm-Kit-for-Air-Pump/M/B0018CLWVA.htm
Generally you'd like to see more than 5 months on an air pump, but they do wear out sooner or later. Usually in my experience it's the diaphragm.
http://pondmaster-usa.com/Replacement-Diaphragm-Kit-for-Air-Pump/M/B0018CLWVA.htm
Generally you'd like to see more than 5 months on an air pump, but they do wear out sooner or later. Usually in my experience it's the diaphragm.