I'm putting together plans to build a pool and have some questions about lighting. I'm looking at the small LED lights that screw into a 1.5" piece of PVC in the wall. The lights are supposed to be 4" below the water surface, so water will obviously enter the PVC when the light is removed when the pool is full. How would the pipe usually be run to prevent it from filling a large portion of the pipe? I would think that water left cutoff from the rest of the pool with a light installed would grow all kinds of algae and the next time there was a removal, the pool would be innundated with that algae.