Need some sprayer help

When I am applying overall roundup I usually do a mix at 2ounces per gallon and run boomless with a ground speed around 4.2 to 4.5mph. Usually takes me a 2.5 gallon container per 8acres. I am trying to kill rough stuff that includes woody stuff. I see they have a eraser blend that contains arsenal which I will be using in the future

good info from canuck,

first of all you need to know the main ways to adjust sprayer output while calibrating. All of these can be adjusted to reach a desired gpa: Ground Speed, RPM, Boom Width, and Nozzle Types.

There are multiple methods for calibrating a sprayer, but the one that is simplest to me is simply measuring off X distance (can be any distance) and drive the tractor for that measured distance and record the time it took along with ground speed (mph) and RPM. You want to calibrate at what will be a comfortable speed while spraying so keep that in mind.

Now you will measure the output of the sprayer by collecting the total output of the nozzles for the same amount of time that it took you to drive X distance earlier. (You want each nozzle to put out a volume within 10% of your goal. They can be adjusted).

After that we now have a volume/square feet. To get this into acres we need to cross multiply by 43,560 sq. ft.

This will give you oz per, you can calculate gallons per acre by dividing the oz per acre by 128.

Now let's say my tank Capacity is 150 gallons, I can calculate the amount of product I need to apply by determining how many total acres a full tank capacity will allow me to spray. I'm going to post an example.

Here you go. Now you can do this same calculation to determine product needed per full tank or gallon based on the label recommendations for whatever your target weed is. Hope this helps.

There is a shortcut to sprayer calibration. Determine speed and and pressure ahead of time, then measure nozzle spacing. Convert your mph into feet per second and consult the chart: http://caes2.caes.uga.edu/commodities/fruits/veg/pubs/documents/1-128%20Acre%20Sprayer%20Calibratio.pdf. Determine the number of seconds to cover the distance on the chart. Then all you have to do is catch one nozzle sitting still for that timing and the number of ounces collected is your GPA. Your can get a card with the chart on it for free from the extension office.