Pool scale, etching & water balance (LSI)
Crusty scale means your water balance (LSI) is too high; rough, etched plaster means it’s too low. The Langelier Saturation Index combines pH, temperature, calcium, and alkalinity into one number — keep it near zero.
Step by step
- Check your LSIThe DoseMyPool app computes LSI from your readings and tells you which lever to move.
- Lower pH first for scaleIt’s the fastest lever — bring pH to ~7.4. For corrosion, raise calcium and alkalinity into range.
- Fix calcium lastIf calcium is far out of range, partial drain-and-refill is the only real way down.
FAQ
What LSI is balanced?
Roughly −0.3 to +0.3 is considered balanced. Negative is corrosive, positive is scale-forming.
Related
Stop guessing — get the exact fix
DoseMyPool turns your test numbers into the precise doses and the safe order to add them. Free on the App Store.