Quote Originally Posted by 2dogpool
Not to sound too stupid but......no, doesn't help at all!!! What is the Langelier Saturation Index?????
Something you really don't have to worry about if you keep tabs on your pH and keep your water balanced as eveyone on here will help you to!

The Langelier SI is something that was designed for closed systems like boilers and the majority of the pool industry has bought into it because:
1) They didn't have anything better
2) It help to sell a LOT of unnecessary chemicals!

It really isn't applicable to an open system like a swimming pool. If you have a heater or grouted tilework you probably do need some calcium in your water but the pH is going to be the main factor that determines how aggresive or scaling your water is. The SI is a rough guide at best and changes with the temperature. Ben pointed out in one post how people are careful to balance it for the water temperature in their pool but don't take into account that the water temperature inside the heat exchanger is higher and that their water is no longer balanced!

Bottom line...Don't lose any sleep over the Saturation Index no matter what dire consequences the pool store might tell you will happen!