Dosing, Stock Solutions & Jar Test Reference
The quantities of product required are tiny, and using too much will result in the opposite of the intended result. These revised instructions and reference tables replace the original printed sheet.
Read This Before Mixing
PAC, PFS, and PAM are not 100% pure — they contain roughly 30%, 20%, and 90% active content, respectively. That has to be taken into account when dosing your water.
For example: if you have 5 gallons of very dirty water and you're using 20% PFS in a 5% stock solution (50 g per 1 L water), each mL of that diluted solution contains 10 mg of active PFS. High-turbidity water starts around 500 mg total PFS, meaning roughly 50 mL of solution — but you'll likely want to stay under 100 mL. Start low, slowly increase the dose, and verify pH remains in an acceptable range as you go. Adjust as needed.
Choosing a PAM Grade if the Water Will Be Consumed
You should prefer Anionic PAM (APAM) or Non-ionic PAM (NPAM) for any scenario where the water might be consumed. Cationic PAM (CPAM) is used for sewage treatment — see Which PAM for the full grade-selection guide.
Dose Ranges & Stock Solutions
| Chemical | Light turbidity | Medium turbidity | High turbidity | Optimal pH |
|---|---|---|---|---|
| PAC | 2–8 | 8–20 | 20–50 | 6.0–7.5 |
| PFS | 5–12 | 12–25 | 25–50 | 5.5–7.0 |
| PAM | 0.1–0.3 | 0.3–1.0 | 1.0–2.0 | —† |
| Chemical | Product active % | Solution strength | Grams in 1 L water | mg active / mL |
|---|---|---|---|---|
| PAC | 30% | 1% w/v | 10 | 3.0 |
| PAC | 30% | 5% w/v | 50 | 15.0 |
| PFS | 20% | 1% w/v | 10 | 2.0 |
| PFS | 20% | 5% w/v | 50 | 10.0 |
| PAM | 90%‡ | 0.01% w/v | 0.1 | 0.09 |
| PAM | 90%‡ | 0.1% w/v | 1 | 0.9 |
| PAM | 90%‡ | 0.025% w/v (1 g / 4 L) | 0.25 | 0.225 |
Chemical Amount by Batch Volume
Dose range × batch volume, for the five volumes you're likely mixing. Light / Medium / High are source-water turbidity levels, not chemical strength. Each mg figure is milligrams of that table's named chemical (active ingredient) needed for the whole batch.
30% PAC
| Volume | Light turbidity (mg PAC) | Medium turbidity (mg PAC) | High turbidity (mg PAC) |
|---|---|---|---|
| 0.5 L | 1.0–4.0 | 4.0–10 | 10–25 |
| 1 L | 2.0–8.0 | 8.0–20 | 20–50 |
| 1 gal | 7.6–30 | 30–76 | 76–189 |
| 2.5 gal | 19–76 | 76–189 | 189–473 |
| 5 gal | 38–151 | 151–378 | 378–945 |
20% PFS
| Volume | Light turbidity (mg PFS) | Medium turbidity (mg PFS) | High turbidity (mg PFS) |
|---|---|---|---|
| 0.5 L | 2.5–6.0 | 6.0–13 | 13–25 |
| 1 L | 5.0–12 | 12–25 | 25–50 |
| 1 gal | 19–45 | 45–95 | 95–189 |
| 2.5 gal | 47–113 | 113–236 | 236–473 |
| 5 gal | 95–227 | 227–473 | 473–945 |
PAM
| Volume | Light turbidity (mg PAM) | Medium turbidity (mg PAM) | High turbidity (mg PAM) |
|---|---|---|---|
| 0.5 L | 0.05–0.15 | 0.15–0.50 | 0.50–1.0 |
| 1 L | 0.10–0.30 | 0.30–1.0 | 1.0–2.0 |
| 1 gal | 0.38–1.1 | 1.1–3.8 | 3.8–7.6 |
| 2.5 gal | 0.95–2.8 | 2.8–9.5 | 9.5–19 |
| 5 gal | 1.9–5.7 | 5.7–19 | 19–38 |
Tiers interpolated from the overall dose ranges above — there isn't a single published light/medium/high split, so treat these as jar-test starting points, not fixed thresholds. Always confirm against your product's data sheet and run your own jar test.
† PAM has no independent pH optimum — it's dosed during slow mix, after the coagulant's pH has already been set.
‡ PAM is treated as ~90% active polymer solids. If your product's data sheet states a different active content, apply the same correction formula used for PAC/PFS.
§ Batch-volume tables use 1 gal = 3.78 L, matching the stock-prep calculations above.
¶ The difference between 90% and 100% active PAM is tiny in practice — if you'd rather skip the extra multiplication step, it's safe to simplify by treating PAM as 100% active.