In the picture of your first post it looks like your inlet (from the skimmer) is high up on the pump skimmer basket. If you close the valve right before the pump, then fill the pump skimmer with water, does the water stay level with the top? Or does it drain out?
The poly to PVC transition at the pad is fully accessible and there are no leaks that I can see – I replaced that when I re-plumbed and left it uncovered for testing. I cut off about 4 inches (where the old barb connector was) and added a new fitting and pipe clamps. Seems solid. I've attached a better pic where you can just about see it – the soil below the fitting is only wet because I emptied the pump to check the impeller.
At the other end, there's an elbow on the bottom of the skimmer and I assume that's directly connected to the poly. The skimmer is tiny so I'll only need to dig down about 14 inches to get to the line below it. I lifted one of the pavers next to the skimmer and it looks a bit like the skimmer is bedded in sand and crushed stone so maybe it won't be too tough to dig down.
Ok, then it’s definitely gonna be in that line.
Unless you find the leak is right at the skimmer connections, it looks like you’ll have to dig up that pipe. If that is the case, then you might be better off installing new PVC plumbing all the way to the pad. (Fingers crossed that it’s not to difficult)
You could temporarily run it above ground with poly for a temp fix til after the season. Make sure if you attach to poly barb fittings you dont use use clamps like in the pic. Use 2 clamps but rotate the 2nd one 180 degrees so the nut is on opposite side. They can leak under the void of the clamp mechanism
I have a temporary fix in place using some fittings from the old plumbing. It's not ideal because it's partially flex, and I had to cut it 1/4-inch shorter than it should be to squeeze it in between the fittings but it should hold for the three months I have left of the season.
Clamped exactly as you described @jimmythegreek
No leaks so far but I'm going to keep the hole open to monitor for a few days while I SLAM the pool. The pump is priming nicely and keeping prime, at least while running – first time since I've owned the house I've had no bubbles in the returns! Thanks for sticking around Rob!