What is the best Calcite Saturation Index (CSI) for a saltwater pool

[chem geek]

I wouldn't worry about the winter since the colder water temperature will naturally have the pH move upward, all else equal (so let the pH drift up on its own to 7.6 or so during the winter). As for the summer numbers, the roughly -0.2 saturation index is fine since you don't want scaling in the salt cell where one plate is at high pH. Since you are using borates and keeping a lower TA to avoid the rate of pH rise (I assume), you have a higher than average CH to compensate. This all looks good.

Richard

[smallpooldad]

chem geek,

Thank you for your very quick reply. Yes the 70 setting is so we do not have to compensate for pH too often. The 7.5 pH we try to achieve to offset Hawaii's Volcanic Dust, aka Brown Dirt (Ferric Oxide or Iron Rust), which blows in at 16 mph to 26 mph. At higher pH(s), as you know, it goes out of solution and stains the pool brown.

One quick quetion should I use a CYA adjustment for Alk or is it in your spreadsheet?