pH
- What: Measures water acidity/alkalinity (scale: 0–14, neutral at 7)
- Ideal Range: 7.4–7.6
- Why It Matters: Affects comfort, chlorine effectiveness, and prevents corrosion/scaling
- Test Frequency: Daily or 2–3x/week
- Adjustment: Increase with soda ash; decrease with muriatic acid or sodium bisulfate
Total Alkalinity (TA)
- What: Buffering capacity against pH changes
- Ideal Range: 80–120 ppm
- Why It Matters: Stabilizes pH; prevents corrosion (low) or scaling (high)
- Test Frequency: Weekly
- Adjustment: Increase with baking soda; decrease with acid
Calcium Hardness (CH)
- What: Measures calcium levels in water
- Ideal Range: 200–400 ppm (Plaster: 250–350 ppm; Vinyl/Fiberglass: 150–250 ppm)
- Why It Matters: Prevents etching (low) and scaling (high)
- Test Frequency: Monthly or when refilling
- Adjustment: Increase with calcium chloride; decrease by dilution
Free Chlorine (FC)
- What: Active chlorine for sanitization
- Ideal Range: 1–3 ppm (varies with CYA)
- Why It Matters: Kills bacteria, algae, and contaminants
- Test Frequency: Daily or 2–3x/week
- Adjustment: Increase with liquid chlorine, tablets, or shock
Total Chlorine (TC)
- What: Free chlorine + combined chlorine (chloramines)
- Ideal Range: Close to FC (<0.5 ppm difference)
- Why It Matters: High chloramines cause odor/irritation, indicating the need for shocking
- Test Frequency: Weekly or if issues arise
- Adjustment: Shock pool to break down chloramines
Cyanuric Acid (CYA)
- What: Protects chlorine from UV breakdown
- Ideal Range: 30–50 ppm (up to 100 ppm in hot climates)
- Why It Matters: Low CYA = fast chlorine loss; high CYA = reduced sanitization effectiveness
- Test Frequency: Monthly or after adding stabilized chlorine
- Adjustment: Increase with CYA; decrease by dilution
Total Dissolved Solids (TDS)
- What: Sum of all dissolved substances (salts, minerals, etc.)
- Ideal Range: <1,500 ppm (higher in saltwater pools)
- Why It Matters: High TDS affects water clarity and sanitizer efficiency
- Test Frequency: Monthly or if water looks off
- Adjustment: Dilution with fresh water
Phosphates
- What: Algae-feeding nutrients from debris, fertilizers, etc.
- Ideal Range: <100 ppb
- Why It Matters: High levels promote algae growth despite proper chlorine levels
- Test Frequency: If algae persists
- Adjustment: Use a phosphate remover
Metals
- What: Trace metals from water sources or corrosion
- Ideal Range: Near 0 ppm
- Why It Matters: Causes staining, discoloration, or green water
- Test Frequency: If staining occurs
- Adjustment: Use a metal sequestrant
Temperature
- What: Pool water temperature in °F or °C
- Ideal Range: 78–84°F (26–29°C)
- Why It Matters: Impacts chlorine demand and scaling risks
- Test Frequency: As needed
- Adjustment: Use heater or natural cooling
Langelier Saturation Index (LSI)
- What: A formula that measures water balance for corrosion or scaling risks
- Ideal Range: -0.3 to +0.3 (0 = balanced)
- Why It Matters: Prevents corrosion (-LSI) or scale formation (+LSI)
- Test Frequency: Monthly or with major parameter changes
- Calculation: Calculations can be complex, but user-friendly online calculators make obtaining quick and accurate results easier.
Chlorine to CYA Ratio
- What: Relationship between FC and CYA levels
- Ideal Range: FC = at least 7.5% of CYA
- Why It Matters: Ensures adequate sanitation regardless of stabilizer levels
- Test Frequency: When testing FC & CYA.
- Calculation: Minimum FC = CYA ÷ 13.3
Chemical Adjustment Rules of Thumb
- pH: 1 lb soda ash per 10,000 gallons raises pH by ~0.6.
- TA: 1.5 lbs baking soda per 10,000 gallons raises TA by ~10 ppm.
- CH: 1 lb calcium chloride per 10,000 gallons raises CH by ~10 ppm.
- CYA: 3 oz cyanuric acid per 10,000 gallons raises CYA by ~10 ppm.
Seasonal Opening/Closing Adjustments
Common Pool Chemistry Problems & Quick Fixes
Even with the best intentions, pool chemistry can sometimes go off track.
Cloudy Water
Algae (Green, Black, Yellow)
Strong Chlorine Smell & Eye/Skin Irritation
- Cause: High chloramines (combined chlorine) occur when chlorine reacts with sweat, urine, and other organic matter.
- Solution: Shock the pool to eliminate chloramines. Ensure FC is 1–3 ppm.
Scale Buildup (White, Crusty Deposits)
Etching or Pitting of Plaster/Grout
- Cause: Low calcium hardness and low pH.
- Solution: Increase calcium hardness to 200–400 ppm and maintain proper pH.
Salt Water Pool Chemistry Cheat Sheet
Saltwater pools work by turning salt into chlorine, but they still require chemical balance. Learn How to Convert to a Saltwater Pool.
| Parameter |
Ideal Range |
Test Frequency |
| Salt Level |
2,700–3,400 ppm (check manufacturer specs) |
Monthly |
| ORP (Oxidation-Reduction Potential) |
650-750 mV |
If the automated controller is used |
Salt Level
- What: Sodium chloride concentration for chlorine generators.
- Ideal Range: 2,700–3,400 ppm (check manufacturer specs).
- Why it matters: Ensures proper chlorine production.
- Test Frequency: Monthly.
- Adjustment: Add pool salt or dilute.
ORP (Oxidation-Reduction Potential)
- What: Measures water’s sanitizing power.
- Ideal Range: 650–750 mV.
- Why it matters: More accurate than chlorine ppm readings.
- Test Frequency: If using an automated controller.
- Adjustment: Modify chlorine and pH levels.
FAQs About Pool Care Cheat Sheet
What order do you correct pool chemistry?
The correct order for balancing pool chemistry is:
- Total Alkalinity (provides foundation for stable pH)
- pH (affects most other chemical processes)
- Calcium Hardness
- Sanitizer (chlorine)
- Stabilizer (cyanuric acid)
- Other treatments (algaecides, clarifiers, etc.)
What is the ideal chemistry for a pool?
The ideal chemistry for a pool includes a ph of 7.4-7.6, total alkalinity of 80-120 ppm, calcium hardness of 200-400 ppm, free chlorine of 1-3 ppm, and cyanuric acid of 30-50 ppm. For more information, see our Chlorine Pool Chemistry Cheat Sheet, which explains the parameters and their reasons. None of the other ranges can guarantee the desired ratio of the supplied chemicals for optimal performance, designed comfort, and equipment protection.
What are the 3 C’s of a pool?
The 3 C’s of pool maintenance schedule are:
- Circulation: Proper water movement prevents algae and distributes chemicals
- Cleaning: Regular skimming, brushing, and vacuuming
- Chemistry: Balanced water parameters for safety and clarity
How do I calculate how much chemical I need for my pool?
To calculate chemical dosage:
- Determine your pool volume in gallons (Tips: How to Calculate Pool Pump Run Time [Calculator Included] )
- Use test results to find how far off your current level is from the ideal range
- Follow the “Chemical Adjustment Rules of Thumb” section, adjusting for your pool’s volume
- Always add chemicals in smaller increments, retest, and adjust as needed
What regular maintenance should be done on a pool?
Regular pool maintenance checklist should include:
- Daily: Skim surface debris, check chlorine and pH levels
- Weekly: Vacuum pool, brush walls/floor, check and adjust all chemistry, clean skimmer baskets
- Monthly: Clean filter, check total alkalinity and calcium hardness, check for leaks
- Quarterly: Check equipment, deep clean filter, test for metals and phosphates
Do I really need to shock my pool every week?
Not necessarily. Shocking frequency depends on:
- Bather load (how many people use the pool)
- Weather conditions (heat, rain, etc.)
- Current chlorine readings
- Presence of algae or cloudiness
For lightly used residential pools with properly maintained chlorine levels, shocking every 1-2 weeks in summer and monthly in cooler weather is often sufficient.
Key Takeaways
By now you may have a deep understanding of how to keep your chlorine or saltwater pool clean and pure. Keeping a well-balanced pool chemistry is the key to a safe and clean swimming environment. Consistent testing and adjustments keep your pool crystal clear. Bookmark this cheat sheet for easy reference.
