Blue Haven pools built our pool around 2001. We have a “Blue Haven Pools 450 & 550 series cartridge filter”. One of the two tension springs for the compression band that holds the two piece filter housing together has a stripped nut or stripped threaded shaft, we haven’t been able to remove it yet, don’t want to destroy it without a replacement. I’d like to change to whole band with compression spring assemble or just the one side compression assembly if possible. The problem is trying to find a compatible part for a filter housing that old. Can you direct me please? I’ve attached a pic to help identify the unit.