I have had my pool for about 7 months now. I finally got around to locating that darn leak. I could tell it was a static leak by how quickly the water left when it was full and as it leaked out the leak would get slower and slower no matter how much I ran my pump. I finally drained the pool to get some stain fighting action and leak detection going on. The attached pics are what I found behind the light. Now I know I can get a rubber stopper to go in the hole for a single line but with that grounding wire coming through, what is the best way to seal the hole?