Does your swimming pool have a screen enclosure?
With screened pools, you would think it get less dirty. But that is not the case. Yes, it would not get that many leaves in it (as long as you don't have plants around the pool). But, however it does get worms, bugs, and dirt in the pool.
Most screen pools just have the basic screen to try and keep bugs out, but even that doesn't always happen. As time goes by, if you are not cleaning your screen for dirt, then mold and phosphates can collect on the screen itself. So, that means when it rains it all get washed into your pool. Then the pool starts to turn green and that is not good.
We clean the pool, but not the screen (there is an extra charge to clean your screen enclosure). So, we recommend at least twice a year having the screen enclosure pressure cleaned to prevent this. A cleaning of your screens should be completed right before rainy season.