Mysterious connection

[grichard]

There's an inlet or outlet in my pool whose function is a mystery to me. It's smack in the middle of the bottom of the pool, right where the shallow part starts to slope down into the deep end. It looks to be about 1.5" in diameter and is closed with a threaded PVC cap. It's pretty much flush with the bottom of the pool.

It resembles the connection for my pressure-side cleaner, which is located on one of the sidewalls about 6" below the waterline. Could this be an alternative hookup for a cleaner like that? Any idea what else it might be?

Thanks!

 

[RobertFlagg]

Pictures? any extra pipes at your pool pad that your not sure about? In-floor cleaning system?

 

[grichard]

I think I understand everything on the equipment pad; no obvious "other end" to the connection. I can try to send a picture later but it's tricky since it's on the bottom. I'm digging through my old construction photos to see if I have one that shows the plumbing before they shot it.

I don't know much about in-floor cleaning systems. But I didn't ask for one when we built the pool, and a single thing on a 20x40 pool seems like it wouldn't be sufficient.

 

[RDspaguy]

Hey Cards fan, had any Imos lately? I miss Imos SOOOO much!
Who built it? I would call them up and ask.

 

[grichard]

Well, I don't have a picture that shows what it hooks to, but you can see the stub coming up through the gravel in this shot.

 

[grichard]

We've been *trying* not to do too much takeout, but yeah, we break down for the occasional Imo's pie

 

[grichard]

Okay, I called the builder:

It's a "hydrostatic plug" that just goes into the gravel beneath the pool. The idea is to open it if the pool is drained, to allow groundwater to enter and hopefully prevent floating. Apparently there's another one inside the main drain, too.

 

[RobertFlagg]

I guess that makes sense.