I have a underground pool and the PVC "nut" (i don't know what it is) cracked and is letting air into the pipes. When the filter turns off, air rushes in and all the water drains into the pool making it hard for the filter to start again. What is the best way to fix this cracked "nut" on this PVC union? I know when I was replacing the unions on the Salt Cell T15 you could buy replacement nuts that came in two parts and you screwed it together around the PVC so you don't have to cut everything apart and redo it all. Can this be done here? Any idea what this piece is called? As you can see in the pictures, there isn't much room with the PVC length to start cutting and replacing.
As you can see, I tried gluing it together after it cracked but it isn't keeping the union tight enough together, allowing air to come in.