How To Calculate Your Fluoride Feed
Pure Fluoride is 23-25% strength
4 gallons of pure fluoride into 1,000,000 gallons of water = 1 milligram/liter or 1 part/million
To calculate daily usage (dosage) of fluoride you take the number of gallons of water pumped per day x 4; then divide this number (factor) by one million and you will get the amount of fluoride.
(23-25% strength) required to achieve a 1PPM dosage which should equal the number of gallons of pure fluoride pumped out of storage drum daily to treat the water.
Example
Step 1) 250,000 gallons water pumped X 4 = 1,000,000
Step 2) 1,000,000 divided by 1,000,000 = 1
This 1 means 1 gallon of fluoride used out of your storage tank daily to achieve 1 ppm fluoride in your water.
For our example, the city has a natural fluoride of .24 ppm. The state requires municipal water supplies to fluoridate to 1.2 ppm. Therefore, if you feed a dosage of 1 ppm and have a natural of .24 ppm, your residual will be approximately 1.24 ppm, thereby fulfilling state requirements.
Formula to use with any number of gallons pumped:
Number of gallons pumped x 0.000004 = Gallons of pure fluoride pumped.
This formula works for gallons per hour or per day or per week or per month- any time period.
Setting the fluoride pump
Multiply the GPM of well pump x 60, giving you the gallons per hour you pump at the well. Multiply this number by 4. Then divide this number by 1 million. The resulting number will be the number of gallons of pure fluoride you need to feed per hour.
Example
1450 GPM well x 60 = 87,000 gallons per hour.
87,000 x 4 = 348,000
Divide 348,000 by 1 million = .348 gallons of fluoride per hour.
In our example, The LMI pump Model # A-171 pumps 10 gal./24 hr. or 0.42 gal./hr. Divide the gallons needed by the maximum pump output to get pump frequency. In this case 0.348 divided by .42= 83% of pump output. Set stroke at 100% and frequency at 83%. This will give you a dosage rate of 0.348 gallons per hour, which equals 1 ppm dosage