Pool Chemical Balancing Explained
Pool chemistry sounds complicated because the numbers are interdependent, not because any single reading is hard to understand. Cinco Ranch and the surrounding Katy-area MUD communities require HOA or architectural-committee approval before pool construction starts; that approval step is handled during design, not after excavation begins.
The Four Numbers That Matter
Free chlorine (or bromine) is the sanitizer killing bacteria and algae; pH measures how acidic or basic the water is; total alkalinity is a buffer that keeps pH from swinging; and calcium hardness measures dissolved minerals that affect plaster and equipment.
Of the four, pH and alkalinity move together. Alkalinity below about 80 ppm lets pH bounce around with every rain event or chemical addition; alkalinity above about 120 ppm makes pH stubborn and hard to correct. Fix alkalinity first, then dial in pH.
A Practical Order of Operations
Test alkalinity and pH before adding sanitizer. If alkalinity is out of the 80-120 ppm range, correct it with the appropriate increaser or decreaser and retest the next day before touching pH.
Once alkalinity is stable, adjust pH into the 7.2-7.6 range. Only then does chlorine work as efficiently as it should; chlorine added to water with the wrong pH is partially wasted, which is a common reason a pool "won't hold chlorine" even with frequent dosing.
FAQs
How often should I test pool water?
Twice a week is a reasonable baseline for most residential pools in the Houston area given the long swim season, more often during heavy use (parties, frequent rain) or right after shocking.
Why does my chlorine reading keep dropping overnight?
UV exposure burns off unstabilized chlorine, and heat accelerates the process; a cyanuric acid (stabilizer) level in the 30-50 ppm range protects chlorine from sun loss without over-stabilizing the water.
Where This Fits
See our Pool Repair service page, or Financing if cost is the next question.
Related Reading
Pool Stain Identification and Removal
How to tell metal stains from organic stains from scale, and what actually removes each type.
Total Dissolved Solids (TDS) Explained
What TDS actually measures, why it climbs over time, and when it finally means draining some water.
How to Fix Green Pool Water
A step-by-step approach to clearing algae-green pool water, from diagnosis to shock to filtration.
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