Polaris Backup Valve & Hose Compression Fittings

[JTGrace]

I am trying to replace my Polaris Backup Valve, but can't disconnect the hose from the top and base of this giant white acorn. I have tried unscrewing the compression fittings (nuts), but it just keeps spinning and never backs off. I have also tried simply pulling it off (caveman style), but that didn't work either. What's the trick?

[czechmate]

Backup valve is 2 parts shell, screwed together in middle.
It is fairly hard to unscrew without leaving a channelocks marks on the plastic.
Usually hitting it while fastened in a vise works beter than steadily applied pressure by chanelock pliers. (Always wrap in old leather gloves to minimize damage).

[mandycole24]

Did you find a solution to this? I am having the same problem