What inputs does the chlorine dose calculator use?
It uses pool gallons, current free chlorine, target free chlorine, and the chlorine product strength. Those four inputs change the dose more than the generic label directions on a bucket.
Free Pool Tool | Ellis County, TX
Pool Chlorine Dose Calculator
Calculate a practical free chlorine dose for North Texas pools without trusting the back of the bucket.
Quick answer
How much chlorine do you add?
To raise free chlorine in a 15,000-gallon pool by 3 ppm, add about 48 fl oz of 12.5% liquid chlorine or about 60 fl oz of 10% liquid chlorine.
That estimate assumes you are dosing the gap between your current free chlorine and target free chlorine. Use the calculator below for your exact gallons, starting reading, target, and product strength.
Calculator
Enter your pool numbers
Fractions like 1/4 or 1/8 work in number fields. Results are planning estimates, not a binding service diagnosis.
Result
42.8 oz Liquid chlorine 12.5%
Add in portions when making a large correction, circulate, and retest.
Pounds2.68 lb
Increase2 ppm
How to use the dose
How to add a chlorine dose
Test free chlorine, calculate the ppm increase, add the matching chlorine dose with the pump running, and retest before swimming.
- Test free chlorineUse a DPD or FAS-DPD kit and enter the free chlorine reading, not total chlorine.
- Choose the targetEnter the free chlorine target you want to reach and select the chlorine product strength printed on the label.
- Add with circulationPour the calculated dose with the pump running and never mix chlorine with acid or other chemicals.
- Retest before swimmingWait for circulation, then confirm free chlorine is back in the normal range on your test kit before swimming.
Pro Take
You can do this yourself. Or you can stop chasing it.
If chlorine disappears after every dose, the problem is usually CYA, algae, turnover, or weak product. A&M can diagnose the cause instead of selling you another bucket.
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How to test
Get the reading before you dose
Use a DPD or FAS-DPD kit that reads free chlorine, not just total chlorine.
- Never mix chlorine with acid or other chemicals.
- Add chlorine with the pump running.
- Do not swim until free chlorine is back in the normal range on your test kit.
Companion Guide
How Much Chlorine Should I Actually Add to My Pool Every Week?
Read the paired blog post for the plain-English version of the chemistry, testing, and common homeowner mistakes.
Read the guideFAQ
Free Chlorine Dose Calculator FAQs
Should I enter free chlorine or total chlorine?
Enter free chlorine. Total chlorine includes combined chlorine that has already reacted with contaminants, so using total chlorine can make the calculator under-dose a pool that has no active sanitizer left.
Why does the selected chlorine product change the dose?
Liquid chlorine, cal-hypo, and dichlor deliver different available chlorine per ounce. The calculator converts your ppm increase into the right ounces for the specific product you picked.