Free Calculator · Published October 2026
Chemical Feed Rate: Pounds per Day from the Operator Sheet
Turn a dose and a flow into pounds per day before the pump setting is copied from memory.
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Book a DemoA Chemical Feed Rate Uses 8.34 and Divides by Purity
This chemical feed rate follows the Florida DEP operator formula sheet, revised February 2014. A one-time casing dose stays on the chlorine dose calculator.
The dose you intend to feed, not a residual you measured.
Use the unit in the next field. Do not mix them.
Gallons per minute use 1,440 minutes in a day.
100 means you divide by 1. 65 means you divide by 0.65.
Only if you also want pump gallons per day.
Important: All calculator results are ballpark estimates
All calculations are estimates based on historical information and should be verified by the user. This tool is provided as a free service for planning purposes only and is not a substitute for a professional assessment, a supplier quote, or applicable local code requirements.
What the Chemical Feed Rate Is Using
Pounds per day sit above the line
The sheet's chemical-feed pie puts pounds per day above the horizontal line. The wedges below are million gallons per day, milligrams per liter, and 8.34 pounds per gallon. The note says to multiply those wedges and divide by purity as a decimal. Sixty-five percent is written there as 0.65.
A feed at 100 percent purity is dose times flow times 8.34. The same dose at a lower purity is a larger product weight, because you divide by a number smaller than 1. The tool does not guess a purity. You type it.
Worked examples
One milligram per liter at 1 million gallons per day and 100 percent purity is 8.34 pounds per day. Two milligrams per liter on that same flow is 16.68 pounds per day. At 65 percent purity the 16.68 is divided by 0.65. Ten gallons per minute is 10 times 1,440 divided by 1,000,000, which is 0.0144 million gallons per day.
| Case | MGD | lb/day |
|---|---|---|
| 1 mg/L, 1 MGD, 100% pure | 1 | 8.34 |
| 2 mg/L, 1 MGD, 100% pure | 1 | 16.68 |
| 2 mg/L, 1 MGD, 65% pure | 1 | 25.6615 |
| 2 mg/L, 10 gpm, 100% pure, 12.5% solution | 0.0144 | 0.2402 (0.2304 gal/day of solution) |
A feed rate is not a residual
The public chloramine and chlorine rows, both printed at 4.0 on the national primary page, are explained in chloramine in drinking water. This calculator does not say you met that row. A continuous injection layout, when that is the equipment question, is the chlorine injection system sizing calculator. Stored cubic feet, if the tank drawing is in cubic feet, are the cubic feet to gallons converter.
What to write on the job ticket
The dose, the flow, the flow unit, the purity you typed, the million-gallon figure, and the pounds per day. If you used a solution strength, write that percent and the pump gallons per day beside it. A water treatment dealer who saves those inputs can rerun the sheet when the flow changes. The result is not a pump curve and not a permit.
Frequently Asked Questions
What does a chemical feed rate calculator change?
It turns a dose in milligrams per liter and a flow into pounds per day. Florida's operator sheet says to multiply flow in million gallons per day, dose, and 8.34, then divide by purity as a decimal. Gallons per minute become million gallons per day with 1,440 minutes in a day.
Why divide by purity instead of multiplying?
The sheet's pie-chart note says the pounds-per-day quantity is above the line, and you divide by purity as a decimal. At 100 percent purity the divisor is 1. At 65 percent, the same pure dose needs more pounds of the product you are actually feeding.
Is this the well shock calculator?
No. The chlorine dose calculator is a one-time dose into standing water in a casing. This page is a continuous feed rate from a flow. It does not pick a shock parts-per-million target.
What is the 12.5 percent solution line?
It is optional. The same sheet says solution pounds per gallon equal the strength as a decimal times 8.34, and pump gallons per day equal the feed in pounds per day divided by that solution strength. 12.5 percent is an example input, not a required product.
Does the result say the residual passed?
No. Pounds per day are not a residual, not a contact time, and not a public MRDL. Chloramine and free chlorine are a different page.
Save the Dose, the Flow, and the Purity
Pounds per day are only as clear as the three inputs that made them.
Get a Free DemoAll calculations are estimates based on historical information and should be verified by the user. This tool is provided as a free service for planning purposes only and is not a substitute for a professional assessment, a supplier quote, or applicable local code requirements. It does not set a disinfectant residual.