I've had an annoying slow leak in my hot tub where there is a 3 inch flange to the control unit. I pulled it apart and found that there is a 3 inch gasket with a break. The gasket looks like a traditional flat gasket but also has an 'o-ring' extension to fill an o-ring groove in the PVC pipe. The unit mates to a aluminum input pipe to the control unit. The gasket looks like this if viewed 'edge on': ================= = <--- flat part ================== || || <--- slot for 'oring groove' I went to Home Depot and Orchard Supply Hardware, no luck. I then looked on the internet, searching for 'gasket'+'spa' and other variants. I find lots of SPA PART places but none of them sell gaskets. I also looked at plumbing supplies with no luck. So..... where else should I look for this simple part that no-one carries? :" title="Question" />

If you have a little play in the pipes, you can get by with just an O ring. The combination gasket/"O" you have is proprietary to the spa industry. Anyone that carries the brand of the control unit you have should be able to get a replacement.