Liquid Chlorine Calculator

1. Convert volume to liters: gal × 3.78541, m³ × 1000.
2. Compute ppm increase: Δppm = max(0, target − current) × (1 + demand%).
3. Available chlorine needed: mg = Δppm × liters (because 1 ppm = 1 mg/L).
4. Convert label to available chlorine: if NaOCl%, available% ≈ NaOCl% × 0.952.
5. Solution mass: grams_solution = grams_available / (available% / 100).
6. Solution volume: mL = grams_solution / density(g/mL).

1. Measure your tank or container volume accurately.
2. Test current free chlorine and enter the reading.
3. Choose a target ppm suited to your purpose.
4. Enter label strength and pick the correct label type.
5. Optional: add a small demand factor for dirty water.
6. Calculate, then measure the dose with a graduated jug.
7. Pre-dilute, add to water, circulate, and retest.

Why free chlorine matters in irrigation

Free chlorine helps control biofilm, algae, and odor-causing microbes in tanks, drip lines, sprayers, and wash bins. When buildup grows, flow can drop and emitters clog. A measured dose supports cleaner water pathways while limiting overuse. This calculator focuses on ppm change and product strength so the amount you add is tied to a clear target and a known volume.

Choosing a practical target ppm

Targets depend on purpose. Light maintenance often uses low ppm to reduce recurring slime. Higher targets are sometimes used for short, controlled cleaning cycles with good circulation and later flushing. Start conservative, retest, and adjust in small steps. The safety reminder field lets you set a personal ceiling so unusually high targets trigger a visible warning before you mix.

Understanding strength labels and conversion

Liquid chlorine labels may state sodium hypochlorite percent or available chlorine percent. They are related but not identical, so selecting the correct label type improves accuracy. The calculator converts sodium hypochlorite to available chlorine using an industry ratio (about 0.952). If your label already lists available chlorine, choose that option to avoid double conversion.

Accounting for demand and contact time

Dirty water, sunlight, warm temperatures, and organic load consume chlorine quickly. The extra demand factor adds a controlled buffer so the predicted dose better matches real conditions. After dosing, allow mixing time, then retest to confirm the achieved ppm. If the reading is low, add a small correction dose rather than doubling, because demand is rarely linear.

Storage, handling, and verification

Strength declines with heat and age, so store containers sealed, shaded, and cool. Use dedicated measuring tools and avoid cross-contamination. Always add chemical to water, never reverse, and never combine with acids or ammonia products. Keep a simple log of volume, target, and test results; this supports repeatable sanitation and helps you tune the demand factor for your site.

1) What does ppm mean in this calculator?

ppm means milligrams of available chlorine per liter of water. A 1 ppm increase equals 1 mg/L, so the required mass scales directly with your total liters.

2) Why is my dose different from a label chart?

Charts often assume a fixed strength, density, and clean water. Your product percent, label type, water volume, and real chlorine demand can shift the dose noticeably.

3) Should I select sodium hypochlorite or available chlorine?

Select what your label states. If it says “sodium hypochlorite 10%,” choose sodium hypochlorite. If it says “available chlorine 8.25%,” choose available chlorine.

4) When should I use the extra demand factor?

Use it when water is visibly dirty, warm, algae-prone, or sun-exposed. Start with 5–15%, retest after mixing, and refine the setting based on repeat results.

5) Can I use this for cleaning tools and surfaces?

It can estimate a mixing dose for wash bins or rinse tanks, but surface disinfection depends on contact time and local guidance. Always follow product instructions and safety rules.

6) What if my target is lower than my current reading?

The calculator will produce zero dose because chlorine cannot be “subtracted” by adding more. Wait for natural decay, dilute with untreated water, or flush the system if needed.