Thanks for your responses gents. Indeed, it is the 2 outlets that are leaking on the outside of the pool wall. All the screws are rusted and, after being exposed for a few days, the area around and below the outlets are always wet. This was in addition to a leaking Tee connection, all 3 connections were leaking and all the screws were rusted solid, almost like welded by rust. I fixed that but, after re-assessing the whole pipe work around the pool, mostly black poly, I decided to replace everything and do it correctly. The black poly was going up and down along the pool, air locks a plenty, which explains why I always had issues in winterizing the pool and clearing the water lines.

The technicians are coming over tomorrow morning to replace the 2 outlets. The chap I talked to yesterday does not like the idea of having schedule 40 hard pipe connected directly to the outlets. He favours the flexible PVC connection, mainly because, here in Ontario, it gets very cold in winter and he's concerned that the sand movements, freezing and thawing, will eventually break the connectors. They have done hundreds of pool installations around the Ottawa area, so I will trust his recommendations, but I will still install the rigid sched 40 pipes for the rest, which will be buried at 18 inches below the surface. I do need to have that slope toward the returns for proper drainage in the fall.

I could post some before/after pictures if anyone is interested.

The final digging spree will be done today as I drain the pool. It's going to be hard work as they forecast a temperature of 34C today. Ugh...

Any other tips/suggestions for the piping installation?

Thanks folks, I appreciate your assistance!

Pool Slave