You have to always keep chlorine tablets in the pool and shock it once a week, and take a sample of water to a pool store where they will analyse it at no cost and tell you whatever else you need to put in it. Whenever you buy a packaged pool the size of yours it can be a real pain to keep up, not to mention costly. The pumps that come with it are really really too small and barely do anything to keep your pool clean. I ended up buying a large pump for my 4" pool and it worked out a lot better. Also, my niece worked at a pool store once and she told me that baking soda works just as well as some of the expensive chemicals but I'm sorry I don't remember exactly what she said it was for, to lower or raise the ph alkaline level, or something.
Shock (chlorine) when you first open the pool. You'll need ph rise and ph lower and alkalinity rise and alkalinity lower. Your pool company will sell you a bunch of crap and tell you you need this and that if you bring them a sample of your water (cause thats how they make money). I always used Enjoy once a week and my water was crystal clear all year long. You need to adjust ph and alkalinity when it rains a lot. Pools are a lot of work but if you keep up on it it wont cost you much for the season.
Chlorine & ph up & ph down...purchase a testing kit as well.♥