Learn pool chemistry

Plain-English guides to the numbers on your test kit — what they mean, what they should be, and exactly what to add when they're off.

• How to Lower Pool pH (and Keep It Down)

  Why pool pH drifts up, how much acid to add, the safe way to add it, and why lowering pH also lowers alkalinity.

  Updated October 10, 2026

• How to Raise Pool Alkalinity with Baking Soda

  What total alkalinity does, the 80–120 ppm target, how much baking soda to add, and why to add it in stages.

  Updated October 10, 2026

• Free Chlorine vs Combined Chlorine: What Your Test Is Telling You

  What free, combined and total chlorine mean, when combined chlorine calls for a shock, and why stabilizer changes your free chlorine target.

  Updated October 10, 2026

• Ideal CYA (Stabilizer) Levels for an Outdoor Pool

  What cyanuric acid does, the 30–50 ppm target (60–80 for salt pools), how to raise it, and why the only way down is draining.

  Updated October 11, 2026

• How Much Shock Does My Pool Need?

  How much liquid chlorine or cal-hypo it takes to shock a pool, the breakpoint rule for combined chlorine, and how CYA changes the target.

  Updated October 11, 2026

• Is My Pool Leaking? How to Do the Bucket Test

  How much water a pool normally loses to evaporation, how to tell a leak from evaporation with a bucket, and where leaks usually hide.

  Updated October 11, 2026

• How to Fix Cloudy Pool Water

  The usual causes of cloudy pool water — low chlorine, high pH or calcium, a tired filter, dead algae — and how to clear each one.

  Updated October 11, 2026

• Chlorine Lock: What It Is (and What's Really Going On)

  Why chlorine sometimes seems to stop working, what 'chlorine lock' usually means, and how to fix the real cause — usually too much stabilizer.

  Updated October 11, 2026

• How Often Should I Shock My Pool?

  Why a weekly shock isn't required, the real signs it's time to shock, and how keeping chlorine at target means you rarely need to.

  Updated October 11, 2026

• Salt-Water Pool Basics: How a Salt Cell Works

  How a salt chlorine generator makes chlorine, the salt, CYA and pH levels it needs, and the upkeep that keeps the cell working.

  Updated October 11, 2026

• Phosphates in Pool Water: When to Worry

  What phosphates do in a pool, the levels worth acting on, how much phosphate remover to use, and why chlorine still comes first.

  Updated October 11, 2026