How can I remove the cap from my chlorine feeder?
I found one answer to my own question today. Although I still don't know why the cap was so tight I managed to remove it. At first I used a 2x4 across the cap top and a rubber strap wrench to hold the feeder from turning. But I broke all 4 cap fins plus the pvc fittings which were connected to the feeder.  Then I removed the feeder and placed it in a vise on my work bench. That made me nervous as I was trying not to crack the feeder body. But the cap came off with a strap wrench, finally.  I am still curious to know why the cap was so tight. It felt like a vacuum even after I loosed a bleeder on top of my cartridge filter, I loosened the basket lid on my pool pump, and I removed the broken pvc fittings and any plug I could find on the feeder. The cap was always tight for 12 years but never like this time. Go figure.