Well I'm no Expert....but I am dealing with the same/similar problem.

If that liquid leak sealer works it would be the first actual case I've heard. Not that it doesnt work....I just never heard of any confirmed reports.

An Alternative that I am currently considering:
Fish a tape through the skimmer back to the pump and pull a smaller hose through. You wouldnt get as much volume through the skimmer but this would be a cheap alternative to digging up and patching the broken pipe.

My Main drain is leaking badly and I'm considering pulling a hose this week through it. If it works I'll post in this forum with pictures.

I think you'd want to run a flexible hose rated for pool chemicals. A simple garden hose wouldnt stand up from what I've read.