Part of: Pool Chemistry Basics Series

Pool chemistry cheat sheet: every number you need

5 min read · Updated June 18, 2026

One page. Every target range, every chemical, every quick fix. Bookmark this page — it's the only reference you need poolside.

The master reference table

These are the numbers that keep your pool water balanced, safe, and clear. If you only memorize one table, make it this one.

Parameter	Ideal Range	Too Low	Too High	Test Frequency
Free Chlorine (FC)	2 – 4 ppm (varies w/ CYA)	Algae, bacteria risk	Skin/eye irritation	2 – 3x/week
Combined Chlorine (CC)	< 0.5 ppm	N/A	Chloramines, shock needed	Weekly
pH	7.4 – 7.6	Corrosion, eye sting	Scale, weak chlorine	2 – 3x/week
Total Alkalinity (TA)	60 – 90 ppm	pH bounces	pH hard to lower	Weekly
Calcium Hardness (CH)	200 – 400 ppm	Corrosion, etching	Scale, cloudy water	Monthly
CYA (Stabilizer)	30 – 50 ppm	Chlorine burns off fast	Chlorine becomes ineffective	Monthly
Water Temperature	N/A	N/A	Affects LSI, chlorine demand	With each test
Salt (SWG only)	2700 – 4000 ppm	Low output	Cell damage	Monthly
LSI	-0.3 to +0.3	Corrosive water	Scale-forming water	With each test

PoolChem Tracker has all of these targets built in — log your readings and it tells you exactly what's off and how to fix it. Try it free

Quick fix reference

When a reading is off, here's what to add and roughly how much. All doses are per 10,000 gallons. Always retest after circulating for at least 30 minutes.

Problem	Chemical	Dose Guideline
FC too low	Liquid chlorine	~10 oz per 1 ppm
pH too low	Soda ash	~6 oz per 0.2 pH
pH too high	Muriatic acid	~3 oz per 0.2 pH
TA too low	Baking soda	~1.5 lbs per 10 ppm
TA too high	Muriatic acid	~12 oz per 10 ppm
CH too low	Calcium chloride	~1.25 lbs per 10 ppm
CYA too low	Stabilizer	~13 oz per 10 ppm
CYA too high	Partial drain/refill	No chemical fix

All doses are per 10,000 gallons

These are starting-point guidelines, not exact prescriptions. Pool volume, current levels, and chemical concentration all affect the actual dose. Always retest after adding chemicals and adjust from there.

The adjustment order

When multiple readings are off, don't fix them all at once. Follow this order — each step affects the ones after it:

Total Alkalinity — TA buffers pH. If TA is wrong, pH won't hold no matter what you do.
pH — Once TA is stable, pH adjustments will actually stick.
Calcium Hardness — CH affects LSI and water balance, but won't shift pH or TA.
CYA (Stabilizer) — CYA determines your chlorine target. Set it before adding chlorine.
Chlorine — Now you know your CYA level and can add the right amount of FC.

Skipping this order is the most common reason pool owners chase numbers in circles. The general rule: fix alkalinity first, then work down the list. Exception: if pH is high AND TA is also high, lower pH first — muriatic acid lowers both, so you fix TA as a side effect. If pH is high but TA is low, raise TA first (acid would worsen the already-low TA). The PoolChem Tracker app handles these exceptions automatically.

FC target by CYA level

The "right" amount of free chlorine depends on how much stabilizer is in your water. Higher CYA means you need more FC to maintain effective sanitization.

CYA (ppm)	Minimum FC (ppm)	Target FC (ppm)
30	2.25	3–5
40	3	4–6
50	3.75	5–7
60	4.5	5–8
80	6	7–9

Why does CYA matter so much?

CYA shields chlorine from UV breakdown, but it also binds to chlorine and slows its killing power. The higher your CYA, the more FC you need to keep the same level of sanitization. A pool with FC of 3 ppm and CYA of 80 is effectively under-chlorinated — even though 3 ppm looks fine on paper.

For the full chart with every CYA value from 20–100 ppm, minimum FC, target FC, and shock levels, see the FC/CYA chart →

LSI quick reference

The Langelier Saturation Index tells you whether your water wants to dissolve surfaces (corrosive) or deposit minerals (scale-forming). Here's what each range means in plain English:

LSI Value	Status	What It Means
-0.6 or lower	Very corrosive	Water is aggressively dissolving plaster, metal, and grout. Fix immediately.
-0.3	Slightly corrosive	Water is mildly aggressive. Raise pH, TA, or CH to bring LSI up.
0	Perfectly balanced	Water is in equilibrium — not attacking surfaces and not forming scale.
+0.3	Slightly scale-forming	Water may deposit light scale over time. Lower pH or TA slightly.
+0.6 or higher	Very scale-forming	Heavy scale buildup on surfaces, equipment, and plumbing. Fix immediately.

Your target is an LSI between -0.3 and +0.3. Zero is perfect, but anywhere in that range is safe for your pool surfaces and equipment.

Testing schedule summary

Not everything needs daily testing. Here's a realistic schedule that keeps your pool safe without wasting time or test strips.

Frequency	What to Test
2 – 3x per week	Free Chlorine, pH
Weekly	Combined Chlorine, Total Alkalinity
Monthly	Calcium Hardness, CYA, Salt (if SWG)
With each test	Water Temperature (for LSI calculation)

During heavy use, after storms, or after adding chemicals, test FC and pH more frequently. When in doubt, test.

Skip the cheat sheet — let the app do it

PoolChem Tracker calculates every target, every dose, and every adjustment automatically. Just enter your readings and get instant recommendations.