VisaGage II and Liquid Blockage Monitor Systems (LBMS)

The John Blue Flow Monitor Calculator works on your desktop and laptop computers. It’s used to calculate your flow rate in equivalent gallons per minute per row (based on your fertilizer weight) and helps you determine the most appropriate ball to use in your VisaGage II or Liquid Blockage Monitor System (LBMS) flow monitor device. The calculator is available in both English and Metric units. Instructions for use are available at the bottom of the page.

Choose Unit Preference

Enter Application Rate
Gallons Per Acre
Enter Ground Speed
Miles Per Hour
Enter Row Information
Row Spacing (?)
Number of Rows (?)
Enter Fertilizer Weight
Pounds Per Gallon

I understand that John Blue Company is furnishing this calculator "as is" and that it is not covered by any warranty whatsoever, whether express, implied, or statutory, including, but not limited to, its freedom from errors, its fitness for any particular purpose, and/or its correct or incorrect use. I agree that by using this calculator, I am doing so at my own risk. I agree to hold John Blue harmless for any and all damages directly or indirectly related to the use of this calculator. In no respect shall John Blue Company incur any liability for any damages, including, but not limited to, direct, indirect, special, or consequential damages arising out of, resulting from, or in any way connected to the use of this calculator, whether or not based upon warranty, contract, tort, or otherwise; whether or not injury was sustained by persons or property or otherwise; and whether or not loss was sustained from, or arose out of, the results of this calculator and its use.


I understand that all calculations are based upon the information I provide. Always verify the calculated information before entering the field as variables within your system can cause differences between calculated rates and actual output rates.

Your Estimated Results:

Corrected Flow
Equivalent Gallons Per Minute Per Row
Use this figure to choose the correct ball type for VisaGage II and Liquid Blockage Monitor Systems (LBMS). You'll find the Metric table on the 2nd page and the English table on the 1st page.

Instructions for Use:

  1. Ensure JavaScript is enabled on your device. Most web browsers come with JavaScript installed and already working. (CRITICAL: This calculator will not work without JavaScript functionality).
  2. Select whether you work in “English” or “Metric” units of measurement.
  3. Enter your “Application Rate”.
  4. Enter your “Ground Speed”.
  5. Enter your “Row Spacing” (the distance between crop rows).
  6. Enter the “Number of Rows” being treated.
  7. Enter your “Fertilizer Weight”.
  8. Read the “TERMS OF USE” and the “WARNING”. If you have read, understand, and agree to the “TERMS OF USE” and the “WARNING”, indicate your acceptance by putting a check in the checkbox.
  9. Click the blue button that says, “Click Here To Get Your Flow Monitor Settings”.
  10. Scroll down to the bottom of the page where it says “Your Estimated Results:” to view your CDS-John Blue flow monitor settings.
  11. Match the number in the results field marked “Corrected Flow” with the Visagage II and LBMS Quick Reference Ball Chart to indicate which ball to use in your flow monitor device. A link to the Visagage II and LBMS Quick Reference Ball Chart is provided in the results portion of the form. The data for English units is on the first page and data for Metric units is on the second page.
  12. NOTICE: If after viewing your calculated flow monitor settings, you decide to change any of the input form fields, be sure to resubmit your changes by clicking the blue “Click Here To Get Your Flow Monitor Settings” button once again. Failing to do so will result in improper calculations.