Chlorine

Keep chlorine levels at 3_5ppm. If you run higher it will void your equipment warranty and eat your plaster. No chlorine is needed in winter. 

P.H. How acidic the pool is

Keep the PH around 7.2 _to 7.5

your body is at 7.5. Lower or higher will void any warranty and also eat the plaster. 

Check your pool guy from time to time

Check your own chemicals from time to time. Most pool guys only care that there is no algae and will run the chemicals high to prevent This. This makes the water free of algae ,but eats everything! It’s all in the chemistry education. Some are not as wise as others. 

Salt pools

Salt pool are still chlorine pools it just uses the salt to make chlorine. Do not run the salt high or low. It needs to stay around 3000ppm. You must also add stabilization to the water or the sun will burn off the chlorine that it makes. You also must have a pool and equipment designed for salt use. It cannot go on every pool. You can’t have a lot of stone work or have a non-HD heater or it will all fail prematurely.