Rain water can dramatically effect your water balance, depending on its pH & obviously the quantity of rain. The pH of rain varies across the country generally becoming more acidic as you go from west to east.
As rain falls, it carries down particulate matter that is suspended in the air. This suspended particulate is dust, dirt, soot, chemicals, even bird droppings.
Here's a map showing these pH values (courtesy US EPA, 1999).
Remember that the source water for filling your pool can have certain properties that can cause chemical changes as you top off your pool; especially calcium hardness & metals & minerals. If your tap water is "soft" or "hard", those chemical make ups, make a difference. The use of water softeners makes a difference. PLEASE tell us this information when you contact us so that we can better help you.
Click here for a map of
"hard water" areas.