Pool and Spa connected!?

[Strangelyconnected]

Hi everyone,

Did a whole lot of searching and just couldn't seem to find this issue. My pool and spa are adjacent with a single shared wall, with the spa having an overflow so the water mixes into the pool - so far so good.

However, three or so feet deep, right in the wall the pool and spa share, there is a 2" hole. The inside of the hole is PVC, so this was clearly an original piece of the pool. That said, whatever used to be there isn't anymore, its just a hole now. This is causing the obvious problem of making the spa pretty much useless, seeing as when the valves are switched to spa, the spa drain just sucks in freezing water from the pool!

My only guess is that this was some sort of built-in check valve, so that there was greater water exchange with the pool when the spa drain is off, but that is a complete guess. I'm hoping someone here knows what on earth this thing was, and maybe has some advice as to how to close it (...or at least, it seems to me closing it up is the proper fix). A 2" PVC stopper is exactly the same size of the pipe. A 1.5" PVC stopper is too small. I'm really unsure how to close an underwater hole....

EDIT: It was not easy, but here is a photo of the creature. It's actually...two PVC rings?

 

[kadavis]

Are the pool and spa at the same elevation? If so this is a equalizer line to keep spa at proper water level, some builders did it this way. You need to get the rings out so you can use a threaded plug or expansion plug. Looks like there is a little plaster inside between the ring and fitting.

 

[Richard320]

That looks like a job for a rubber handball or plug.

 

[Strangelyconnected]

Are the pool and spa at the same elevation? If so this is a equalizer line to keep spa at proper water level, some builders did it this way. You need to get the rings out so you can use a threaded plug or expansion plug. Looks like there is a little plaster inside between the ring and fitting.

The pool and spa are indeed at the same elevation. I did a google image search for equalizer lines, and it seems to show it is connected to the pool plumbing normally; this is not, just a hole between the two bodies of water. Can you tell me more about this? Since there is already a "waterfall" overflow that falls from the top of the spa into the pool, what would this hole do in conjunction? When the hole is not blocked off (I currently use a toy to clog it), the spa cannot overflow at all.

Expansion plug - awesome, I'll hunt one down