I've just bought a house and moved in just over a week ago. The previous owner was in pool business for 30 years which he passed it down to his son. He showed me what to do which chemical and I've been following that.
When I tested it, CL and PH was pretty high(He advised me to shock the pool first day I moved in and then every 2 weeks and every one week during hot summer when it's in high use) I think CL was above 3 and PH was more than 8.3 which water seemed to clear to me. I decided to not to add anything to lower CL and PH so I just added water when level was low and left it after it rained(thinking that+sunlight will lower CL and PH) We had couple of rain and Thunderstorm recently. We had thunderstorm day before and yesterday morning before I head out for work, I just glanced at the pool and noticed leaves and other things in it. I figured I would have to clean and put some CL tablets when I come back home.
When I was at work, it rained again so I figured with everything that happened water wouldn't be that clear when I get back home. To my surprise when I came back home after work, other than leaves and other stuff in the pool that fell in during thunderstorm, water was clearer than ever. It could have just been that it was cloudy and water wasn't reflecting much sunlight because of that but I definitely noticed water was much clear than before. Not saying it wasn't clear before the rain and everything but just noticeably clearer after thunderstorm and rain. It's not clear now since I've brushed wall(white powdery cloud comes out when I brushed it. I think it maybe calcium from what I've been reading?)
Could this be because it was too high CL and PH before? When I tested yesterday, CL and PH was at normal range instead of way above 3 for CL and 8.3 for PH.