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Field guides

What each water test tells you, what the target is, and what to do when it's off.

Water chemistry

• Free chlorine →

  What free chlorine measures, the 3–6 ppm target, and why stabilizer raises the minimum you need.

• Combined chlorine →

  Chloramines are used-up chlorine. What the 0.5 ppm ceiling means, why the pool smells stronger when it's high, and how to clear it.

• pH →

  Why 7.4–7.6 is the target, what pushes pH up on salt and plaster pools, and how much acid it takes to move it.

• Total alkalinity →

  TA is what holds pH steady. The 80–120 ppm target, why high TA makes pH climb every week, and how to bring it down.

• Calcium hardness →

  How much calcium is in the water, why plaster needs it and vinyl doesn't, and what to do when the fill water brings too much.

• Cyanuric acid (stabilizer) →

  Stabilizer protects chlorine from the sun and raises the free chlorine you need. Targets, why it only goes up, and how to bring it down.

• Water temperature →

  Temperature drives chlorine demand and feeds the LSI. Why it matters more than techs expect, and when a weather reading will not do.

• Salt →

  Salt level on a chlorine-generating pool. Why the cell label beats any chart, how much a bag moves it, and what low salt does to the cell.

• Total dissolved solids →

  TDS is everything dissolved in the water added together. What the number is actually good for, and why quarterly beats weekly.

• Phosphates →

  Phosphates feed algae. When the reading is worth chasing, when it's a distraction, and where they come from.

• Reading the LSI →

  The LSI tells you whether the water will scale, etch, or leave the surface alone. What the bands mean and which lever to pull.

• The FC–CYA ratio →

  Minimum free chlorine is 7.5% of cyanuric acid (CYA × 0.075). The chart, and why a pool can read in range and still be short.

• Starter chemicals →

  The chemicals to carry on the truck, what each one moves, and how much it takes. Seven cover almost every weekly stop.

Equipment

• Filter PSI →

  The single most useful reading on the pad. Service at 8–10 PSI over clean baseline, and what a low reading means instead.

These guides are one tap away inside FieldSpartan. Every reading on the water-test screen links straight to its guide, and they work with no signal at the pad.