Water Testing & Chemical Balancing

Crystal-clear, safe water isn’t luck, it’s routine testing plus smart balancing. Here’s Pool Life’s practical guide to what to test, how often, and the exact order to balance your pool so it stays clean, gentle on skin, and kind to your equipment.

Why water testing matters

• Health & hygiene: Correct sanitiser kills germs and algae fast.
• Comfort: Balanced pH stops stinging eyes and dry skin.
• Protection: Prevents scale (rough surfaces, blocked heaters) and etching (surface damage).
• Savings: Stable water uses fewer chemicals and less power.

Target ranges (quick reference)

• Free Chlorine (FC): 1–3 ppm (salt pools often 2–4 ppm)
• pH: 7.2–7.6
• Total Alkalinity (TA): 80–120 ppm (fibreglass often 60–100 ppm)
• Calcium Hardness (CH): 200–400 ppm (fibreglass 100–250 ppm)
• Stabiliser / Cyanuric Acid (CYA): 20–50 ppm (salt pools often 60–70 ppm)
• Salt (for SWGs): As per chlorinator spec (commonly 3,000–4,500 ppm)

Targets vary by surface and system. Ask Pool Life for a custom target sheet for your pool.

How often to test

• Summer / heavy use: FC & pH every 2–3 days; full test weekly
• Milder months: FC & pH weekly; full test every 2 weeks
• After big events (storms, parties, heatwaves): immediately, then again the next day

The right tools

• Drop-test kit or photometer: Best accuracy for FC, pH, TA, CH, CYA
• Salt test (if applicable): Electronic meter or dedicated kit
• Test strips: Handy for quick checks, confirm with a drop test if results look odd
• Logbook/app: Note results and doses—you’ll spot trends early

How to take a good sample

1. Run the pump for at least 30 minutes.
2. Collect water at elbow depth, away from returns and skimmers.
3. Test immediately (especially pH and chlorine).

Balance in this order

Total Alkalinity (TA) – the pH buffer

• Low TA: pH drifts wildly. Raise with buffer (sodium bicarbonate) in small doses.
• High TA: pH “floats” high. Lower by adding acid in stages while aerating (water features, returns angled up).

pH – comfort & sanitiser power

• Lower with pool acid; raise with soda ash (small doses).
• Circulate 2–3 hours, then retest before adding more.

Calcium Hardness (CH) – scale/etch protection

• Raise with calcium chloride.
• If too high, the fix is partial drain/refill (and keep pH/TA on the lower end to avoid scale).

Stabiliser (CYA) – sun-shield for chlorine

• Add conditioner slowly (it dissolves over days). Don’t overshoot: high CYA makes chlorine sluggish.
• If CYA is high, dilution is the realistic fix.

Sanitiser (Free Chlorine, FC) – the killer

• Dose liquid chlorine (or adjust SWG output) to land in range.
• If FC is near zero, shock to a high level matched to your CYA.
• For salt pools, use liquid chlorine for major corrections; let the chlorinator maintain day-to-day levels.

Pro tip: Make changes in small steps, circulate, then retest. Big dumps waste money and cause yo-yo chemistry.

Special notes for salt pools (SWGs)

• Keep salt within the manufacturer’s window and clean the cell when scaled.
• In hot, sunny weather, increase pump run time or SWG output to maintain FC.
• Use liquid chlorine for recovery shocks—chlorinators aren’t designed for rapid, high spikes.

Reading the water: quick diagnostics

pH keeps climbing
TA is likely high, or you have a lot of aeration (spillways, spa jets). Lower TA methodically; aim returns down.

Burning eyes / “chlorine smell”
Often, chloramines (combined chlorine), not “too much chlorine.” Shock, improve circulation, and maintain a pH level of 7.2–7.6.

Dusty white scale / rough feel
High pH/CH/TA or warm water. Bring pH/TA to the lower end, consider a scale inhibitor, and brush tiles.

Chlorine disappears daily
Low CYA (sun burn-off) or heavy bather load/organics. Raise CYA into range, brush, and run longer on low RPM.

Algae hints (dull, greenish tinge)
pH ~7.2, shock to a high FC level for your CYA. Brush thoroughly and filter continuously until transparent.

Dosing tips (so you don’t overshoot)

• Circulate first, dose in the deep end, and keep the pump running.
• Split large adjustments into two or three smaller additions with retests between.
• Never add acid and chlorine in the same spot or at the same time.
• Add acid to water, never the reverse. Wear gloves/eye protection.

Optional enhancers (used correctly)

• Clarifiers: Help the filter catch fine particles after storms or heavy use.
• Flocculants: For rapid clearing—settle then vacuum to waste (don’t run through cartridges/DE).
• Phosphate removers: Useful if you have persistent algae plus high debris loads.
• Borates (30–50 ppm): Can stabilise pH and improve sparkle—use with guidance.

Safety & storage

• Store chemicals cool, dry, ventilated, upright, and out of reach of kids/pets.
• Keep chlorine and acid far apart.
• Use dedicated measuring jugs and clearly label everything.
• Rinse and dry gear after use; replace worn O-rings and cracked baskets.

What does Pool Life include in a professional balance visit

• Full lab-grade test: FC/CC, pH, TA, CH, CYA, salt (if applicable).
• Precise adjustments: Dosed in the correct order for a stable result.
• System check: Pump, filter, chlorinator, run-time programming, and circulation tune-up.
• Report & advice: Clear targets, doses, and simple next steps.