“Cover Conundrum

Despite the accident caused by pool drains, many Orlando pool builders, such as Orlando Pools By Design, say you can’t not have them. These drains work by drawing water into pipes, where a filter cleans the water before returning it to the pool. The filter removes dust and debris that could do harm to a swimmer.

The covers are supposed to prevent any part of the body from plunging into the drain. However, as the report states, early cover designs could easily come off accidentally. Newer drain covers feature more holes and fixed installation to keep limbs out of the pool drain without sacrificing the efficiency of the system, as the article states:

The newer drain covers have many more vents than older models do, and are raised up above the pool floor as opposed to being flush against the bottom.”
http://orlandopoolsbydesign.com/orlando-pool-builders-urge-safe-designs-especially-around-pool-drains/