J-PRO-22 Alum Guide Rev 0021622 Page | 14
Formula for Calculating Solution Strength and Settings
How Should I Prepare My Alum Solution?
Note that “mg/L” is the same as “Parts Per Million”, or PPM.
If you added 1 lbs (1-1/4 cups) of Alum to 5 gallons of purified or distilled water, you would end up with
approximately 25,000 PPM solution. This is the solution strength you can start out with in this formula
example below.
The simple formula is:
Flow Rate in Gallons Per Minute (“GPM”) x Parts Per Million of Applied Dosage (“PPM”) x 1440 Minutes
in One Day = Gallons of Alum Used Per 24 Hour Period.
This means, that if your well pump or the pipe that you are injecting the Alum into, runs for 24 hours,
you would use that number of gallons.
Example:
Assume you wanted to inject 10.0 PPM of Alum into your well water. You added 2 lb of Alum with 5
gallons of distilled water, which is approximately a 50,000 PPM Alum solution strength. You know your
well pump flow rate is 12 GPM.
10.0 PPM x 12 GPM x 1440 Divided by 25,000 = 7 Gallons Per Day
What this mean is approximately 7 gallons of the Alum solution will be pumped for every 24 hours your
well pump runs. Your well pump does not run 24 hours each day usually.
For example, If your well runs 2 hours a day, in 12 days you would use about 7 gallons of the diluted
Alum solution.
In our example here, you need an Alum pump that can pump 7 gallons in 24 hours. The JPRO-22 pump
pumps 22 gallons per 24 hours. So: 7 divided by 22 = 30%
Therefore, in this scenario set the JPRO-22 to at 30% speed. If your well flow rate is much lower than
12 gallons per minute, you can use a more diluted alum solution. If your flow rate is higher you can turn
up the speed of the pump.
