It's been a while since it was just the two of us on an episode. To fix that, I am only answering questions from the Scaling UP! Nation, for the whole episode. No guest, no rant from the host, just your questions. Truly, the show for you, by you.

LSI, RSI, PSI

Can you tell us more about LSI, RSI and PSI? (1:04)

LSI, RSI and PSI are all scaling indices. Each tells us whether the water is scaling or non-scaling. Not if the water is scaling or corrosion. ALL water is corrosive.

In 1936, Wilfred Langelier developed a calculation for predicting the pH at which water is saturated with calcium carbonate called pHs. The "Saturation pH" is the first step in all scaling indices.

Saturation pH (pHs):

12.3-(log CaH + log Malk + (0.025xC˚) - (0.011x√)