I have a possibly unusual setup. I have a 40k gallon in-ground pool with a detached spa. The spa is plumbed exactly like a normal spillover spa, except that the spa is level with the pool and is separated by about ten feet of concrete deck from the pool. To keep the spa from overflowing due to bypass water from the pool circulation, there are three PVC pipes, about 1 inch each, that connect the spa to the pool near the water line.
The installation of those pipes is garbage. There's neither gunite nor plaster around them, and the tiles near them are cracked. You can see dirt around the pipes. Everything is currently held together with epoxy, and I'd like to fix it permanently.
Even with the epoxy patch, the pipes are narrow enough that, at high flow, the spa will overflow despite the pipes carrying water to the pool.
The question is: how should I fix it? I could replace the tiles and seal it, but then I have to continue being very careful with the bypass. I could plumb a constant flow valve into the bypass. I could put in bigger pipes, or even a big rectangular PVC pipe if I can find one. Heck, I could go nuts and put in a skimmer with a check valve that goes straight to the pool or a skimmer with a float valve that connects to the pool suction lines.
How is this type of setup usually done? All of the in-ground shared-equipment spas I've ever seen are next to the pool.
If I really wanted to go nuts, I'd separate the bodies of water and see about insulating the spa. This is California, so the pool never closes, but it would still be nice to keep the spa hot all the time.