How to Break the Vacuum Seal on a Pool Cartridge Filter
- 1). Switch off the power to the pool pump. Depending on your pool pump, some pumps may have an “On/Off” switch, while others may need to be turned off at the electrical breaker box.
- 2). Turn the knob on the air relief valve counterclockwise to release the vacuum seal. The air relief value will release the pressure and you will hear a hissing sound as the air leaves.
- 3). Open the filter head by turning it counterclockwise and then pull the filter cartridge out.
Source...