I have an old Southwest Industries portable spa with an attached filter. I am trying to figure out how to release the pressure from it. In the attached photo, there is a gray tab at about 7 o'clock (in the photo) on the filter that jiggles around a bit. Do I pull on this or push it out to release the pressure, or is there something else that releases the pressure?
The label on the filter reads "Caution: Contents under pressure. Turn off pump and open air relief valve before removing filter top."