Consider the duration of the injury. There are two types of back pain: acute and chronic. Acute is a type of injury that is there for a few days and then goes away, best described as coming and going.. Symptoms are often reasonably intense and heal in around four to six weeks.
Pure water usually has a pH around 7. Lemon juice is acid: dissolved baking soda is alkaline. (Properly speaking, dry materials don't have a pH.) Balance chemicals help you to avoid damage to your pool, either in the form of corrosion or scale deposits. Actually, it's a bit more specific than that: balance chemicals allow you avoid problems that result from having too much or too little limestone in the water (calcium carbonate).
Vinyl liner pools do not need the calcium, but the calcium hardness level is still a part of. properly balanced water. If your chlorine is in proper adjustment then move to alkalinity, and so forth down the list. Wait. and retest after each chemical addition to the pool.