Last fall I had an original pool liner (inground ~15k gallon) replaced for a pool installed in 1999 (aesthetics only, no leaks). I also had the original pool light bulb replaced with a ColorSplash bulb. I have a liner covered 'bench' in the deep end and the liner was not flush with the pool sides along the back of the bench seat. Installer said weight of water would eventually settle the fit and we could revisit if not settled by spring. About a month later the light stopped working and appeared to be 1/2 full of water. The liner fit around the bench did look better by this time. Called my installer again, but it was Nov by this time and cold. I was leaving the pool open for the winter (first time) and water level was very high due to excess rain. He said he would need to drain below the light and suggested we wait. Memphis has had excessive rain during entire winter so level remained above top of skimmers the entire time. Last Sunday, heading to mass when water level caught my eye - I could see top of skimmer, but hadn't noticed the day before. By the time I returned from church (maybe 2 hours) water was near to bottom of skimmers. Went to look at pump thinking I had left on backwash, and noticed pool light was on the pool floor. Turned pump off, but water continued to drop and stabilized later in the day even with the bottom of the skimmer molding - ~10" drop. Installer came by and pulled the light out but storms coming so needed to wait. We've had approximately 10-12 inches of rain in Memphis in the past 5 days but pool level remained the same. There are no visible seam separations and installer is mystified, but plans to begin investigating Monday. Installer is established, but individual operator. Since he has not seen this type of occurrence thought I would post and see if others have. Latham liner and American Products light if that makes a difference. Also, water in light appears to be muddy. Thanks in advance for any advice on how to fix.