Pool Setup
1
Free & Combined Chlorine
FAS-DPD titration · R-0870 (×2 scoops), R-0871, R-0003
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Free Chlorine (FC)
1
Rinse the 10 mL sample tube 2–3 times with pool water. Fill to the 10 mL line with a fresh pool water sample.
2
Add two level scoops of R-0870 FAS-DPD powder. Cap and swirl gently until fully dissolved. The sample turns vivid pink / deep red if FC is present. No color = FC is zero, stop here.
3
Using the R-0871 dropper bottle, add drops one at a time, swirling after each. Count carefully.
4
Stop the moment the pink color disappears completely and the sample turns clear. That drop is your endpoint.
5
FC (ppm) = R-0871 drops × 0.5
Example: 8 drops → 4.0 ppm FC
Example: 8 drops → 4.0 ppm FC
Using 2 scoops of R-0870 gives a more vivid initial color and a crisper, easier-to-see endpoint — the drop factor stays the same (× 0.5 per drop). Two scoops is especially helpful at higher FC levels.
If you overshoot: one extra drop past the endpoint turns the sample a faint yellow-clear. In that case, record the count before that last drop as your endpoint.
Total & Combined Chlorine (CC)
1
Fill a clean tube with a fresh 10 mL pool water sample.
2
Add two level scoops of R-0870 FAS-DPD powder and swirl to dissolve.
3
Add 5 drops of R-0003 potassium iodide (KI) reagent liquid. This converts combined chlorine (chloramines) into measurable form. Swirl to mix — color typically deepens or returns if it had cleared.
4
Titrate with R-0871, counting drops until clear. TC (ppm) = drops × 0.5
5
CC (ppm) = TC − FC. A healthy pool has CC < 0.5 ppm at all times.
CC ≥ 0.5 ppm means chloramines are forming — usually caused by insufficient FC, high bather load, or early algae. Requires shocking or a full SLAM.
Enter R-0871 drop counts
drops R-0871
— ppm FC
drops R-0871
— ppm CC
FC = FC drops × 0.5 | TC = TC drops × 0.5 | CC = TC − FC
Leave TC drops blank if skipping the CC test.
Leave TC drops blank if skipping the CC test.
2
pH
Colorimetric comparator · R-0004, R-0007
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pH — comparator block method
1
Rinse the comparator block and both viewing tubes thoroughly with pool water.
2
Fill the large outer tube to the 44 mL line with pool water. Place it in the left-hand slot of the comparator block.
3
Fill the small inner/reference tube to its line with pool water and place it in the right-hand slot. This balances the color of the water itself so you read only the indicator color.
4
Add 5 drops of R-0004 pH indicator to the large outer tube only. Cap and invert gently several times — do not shake.
5
Hold the comparator block at eye level toward natural light (outdoors or near a window — avoid fluorescent lighting). Look through the round windows in the block.
6
Rotate the color wheel or slide the comparator dial until the color behind the wheel matches the sample color as closely as possible. Read the pH value shown.
pH Color Reference — R-0004 Indicator
6.8yellow
7.0gold
7.2amber
7.4orange
7.6red-org
7.8red
8.0dk red
8.2maroon
Ideal range: 7.4–7.6 (orange shades). Below 7.2 = too acidic (yellow-gold). Above 7.8 = too basic (dark red/maroon). The reference tube in the right slot removes the natural tint of pool water so you read only the indicator color.
If FC is above ~10 ppm, chlorine bleaches R-0004 and gives a falsely pale or colorless reading. Fix: add 1 drop of R-0007 sodium thiosulfate to the 44 mL large tube before adding R-0004. This neutralizes the chlorine without affecting pH.
Test pH before other chemistry adjustments on that day — adding chemicals changes pH immediately.
Enter your result
(colorimetric — read from comparator block)
3
Total Alkalinity
Acid titration · R-0007, R-0008M, R-0009
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Total Alkalinity (TA)
1
Rinse and fill the tube to the 25 mL line with pool water.
2
Add 2 drops of R-0007 sodium thiosulfate. Swirl — this neutralizes chlorine that would otherwise interfere with the indicator color.
3
Add 5 drops of R-0008M Total Alkalinity indicator. Swirl — sample turns green or blue-green.
4
Add R-0009 titrant drops one at a time, swirling after each. Color shifts through olive/yellow-green and then toward reddish-pink near the endpoint.
5
Stop at the sharp, permanent color change from green → red/pink. Count total R-0009 drops used.
6
TA (ppm) = R-0009 drops × 10
The endpoint is permanent — one extra drop will not reverse it. If you overshoot, discard and start fresh with a new 25 mL sample.
If the sample looks brownish at the start instead of clearly green, add 1–2 more drops of R-0007 to fully neutralize the chlorine before proceeding.
Enter R-0009 drop count
drops R-0009
— ppm TA
TA (ppm) = drops × 10 | e.g. 9 drops = 90 ppm
4
Calcium Hardness
EDTA titration · R-0010, R-0011L, R-0012
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Calcium Hardness (CH)
1
Fill the tube to the 25 mL line with pool water.
2
Add 20 drops of R-0010 Calcium Hardness Buffer. Swirl — this raises pH so the indicator can form a clean colored complex.
3
Add 5 drops of R-0011L Calcium indicator. Swirl — sample turns wine-red or pink.
4
Add R-0012 EDTA titrant drops one at a time, swirling well after each.
5
Stop when color changes completely from red/pink to a clear pure blue — not purple, not bluish-pink. The transition should be sharp. Count total R-0012 drops.
6
CH (ppm) = R-0012 drops × 10
R-0011L will permanently stain skin, counters, and clothing. Rinse all glassware and the dropper tip immediately after use.
A purple color near the endpoint means you're close — continue one drop at a time until the color is clearly and uniformly blue. Cold water makes the endpoint less sharp; warm the sample slightly if needed.
Enter R-0012 drop count
drops R-0012
— ppm CH
CH (ppm) = drops × 10 | e.g. 25 drops = 250 ppm
5
Cyanuric Acid (Stabilizer)
Turbidimetric · R-0013 Melamine Reagent
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Cyanuric Acid (CYA / Stabilizer)
1
Bring both the pool water sample and the R-0013 reagent to room temperature before testing — cold water produces falsely high CYA readings.
2
Using the CYA mixing tube, fill to the lower mark with pool water and to the upper mark with R-0013 Melamine Reagent (equal volumes).
3
Cap and gently invert the tube 3 times to mix. Do not shake vigorously — this affects the turbidity reading.
4
Hold the tube vertically over the black dot viewing card. Look straight down through the opening at the top.
5
Read the CYA level at the point where the black dot on the card just disappears from view. The scale reads 0 at the top (clearest) to 100 ppm at the bottom.
Results are in 10 ppm steps. If the dot disappears before reaching any scale mark (i.e., CYA >100 ppm), dilute the pool water sample 1:1 with distilled water, retest, then multiply result × 2.
If using trichlor tabs or dichlor as your primary sanitizer, CYA accumulates continuously. Test monthly — it has no chemical removal method other than dilution.
FC Minimum Requirements by CYA Level (TFP)
| CYA (ppm) | Min FC | Target FC | SLAM level |
|---|---|---|---|
| 0 (no CYA) | 1 | 2–3 | 10 |
| 20 | 2 | 3–4 | 10 |
| 30 | 2 | 4–5 | 12 |
| 40 | 3 | 5–6 | 16 |
| 50 | 4 | 6–7 | 20 |
| 60 | 5 | 7–8 | 24 |
| 70 | 5 | 8–9 | 28 |
| 80 | 6 | 9–10 | 31 |
| 100 | 7 | 10–12 | 39 |
Enter your result
ppm (read from dot card scale)
Enter 0 for indoor/fully shaded pools — CYA is only needed to protect chlorine from UV.
Chemical Safety
- Never mix chemicals before adding — bleach + muriatic acid produces chlorine gas.
- Always add acid to water, not water to acid. Pre-dilute muriatic acid in a bucket of pool water first.
- Add chemicals separately, pump running. Space additions at least 15–30 minutes apart.
- Pre-dissolve granular chemicals in a bucket of pool water before pouring around perimeter.
- Calcium chloride dissolves with intense heat — let it cool completely before adding to pool.
- Wait 4+ hours (preferably overnight) after major chemical additions before swimming.
Test Log & CSV Export