Sorry for this obscure question but my wife and I bought a house with a pool this past December. We so far have figured out how to take care of an impeller problem, ammonia problem and (hopefully ? ) finishing up SLAM in the next few days/weeks thanks to this site. However, this random threaded hole is a mystery to us. Upon my wife finding a skink crawling out of it, she promptly wants it closed off if it possible. It is in the deep end above the water line and not near a skimmer. It is a bit larger than a return jet hole and it is threaded. It may be an obvious answer and I’m sorry if it is! Thanks for any help!