You'll want to take a look at www.PoolRepair.com. Very good information on the PoolSchool CDs & PDFs, with 5+ pages on light repair, leaks, etc. Good luck!
I have an inground pool with a significant leak. Through process of elimination and the red food coloring test, I've identified the two sources. They are the pump lines that return water back to the pool. I have have removed my deck boardin and dug enough around them to confirm these are the sources.
Now, my question is on how to repair. I have done a lot of work with sprinkler systems PVC (cutting, adding a coupling, gluing, etc.). However, the elbow on one of these lines is so close to the concrete pool wall, I'm not sure I can remove the cracked elbow and replace the piping. Is it possible to remove the entire line from the pool wall?