The first and most important thing is that you use plain, unscented laundry bleach or 10% or 12% liquid chlorine from a pool store for chlorination. That's both normal chlorination and shocking. You can use Jason's
Pool Calculator to figure out how much bleach it will take to reach the desired level.
In order to avoid adding chlorine several times a day due to sunlight breaking down the chlorine, you add cyanuric acid, also known as CYA or stabilizer to the water. Normally, you want this level to be somewhere between 35 and 50ppm, and it's better to start on the low end since you can't lower it without draining water. Every pool is different, and it may take a season or two to figure out what the right CYA level is for your pool and your schedule. CYA is available at pool stores and at some Walmarts and Lowe's. When adding CYA, it may take as long as a week to fully dissolve.
Your normal chlorine level should be about 7.5% of your CYA level once it dissolves. If your CYA is 35ppm, that comes out about 2.6ppm, so try to keep your chlorine level at 3ppm. You'll lose 1 to 2ppm per day, and maybe more, so it's good to raise it to say 4ppm when you add, so that it's still pretty safe when it drops. Every pool is different, and each pool's chlorine consumption changes daily with weather, swimmer load and a host of other variables.
The absolute key to the whole thing is the ability to accurately test your water regularly. One of the members here sells a really good test kit at
TFTestkits , but in case you think that's just a sales pitch, you can do the same basic thing with a Taylor K-2006, but you won't get it as quickly. Either kit is the best investment you can make in making your pool a fun thing instead of a money pit.
There are other things to test for and control, but it's lunch time, so I'll add more later. Chlorine is by far the most critical.
The next thing to be concerned with is the pH of your water. pH problems can cause eye irritation and change the effectiveness of the chlorine, but the primary concern is the damage it can cause to your pool and equipment. You want the pH to be on the alkaline side of neutral, with 7.4 to 7.6 being ideal, and 7.2 to 7.8 being tolerable. pH is lowered by adding and acid to the water. Hydrochloric acid is available as muriatic acid in hardware stores and home centers. Dry acid, pH Minus is available at pool stores or Walmart. Both accomplish the same thing.
Raising your pH can be done a couple of ways. The most straightforward is to use borax, which can be found with the laundry detergent in most bigger groceries. You can also use washing soda, also known as sodium carbonate or soda ash, found in the same place, but soda ash will also raise your total alkalinity.
