# Help me Calibrate 2.1 gpm electric pump 1/128 method

Discussion in 'Pesticide & Herbicide Application' started by shortgrass01, Mar 4, 2013.

1. ### shortgrass01LawnSite Memberfrom SCPosts: 160

High flo Pump 2.1 gpm 12v / 8amp pump with a 25 gallon Tank.

I marked off 18.5 x18.5 =340sqft

sprayed and timed it, multiple times.

75-80 seconds
Amount collected 104 fluid ounces

so if I have this right; It is going to take 104gallons to spray an acre??

Because a gallon=128 ounces and the test area to be sprayed is 1/128 of an acre, ounces collected=gallons per acre.

I'm missing something, this seem to be a lot of water.

The recommendation is 1 quart of 2,4-d per acre.
If I take the 1 Quart(32ounces) divide by 104gallon=0.3 ounces

This is where I am getting confused, with a 25 gal tank.

Can someone help me with this?

Thanks

2. ### shortgrass01LawnSite Memberfrom SCPosts: 160

At 0.31 ounces per gallon with a 25 gallon tank I should mix 229.20mililiters or 7.75fluid onces of 2,4-d per 25 gallons? right?

3. ### Nate'sLawnCareLawnSite Bronze Memberfrom Nashville, NCPosts: 1,001

That does seem like an awful lot of liquid for the area you're testing. It's taking you 75 to 80 seconds to cover 340 square feet? How many and what type of nozzles are you using and what is your travel speed? Based on what you've calibrated to, your calculations are probably right, but you should be able to cover it faster, resulting in less liquid required. I built a spread sheet with different spray rates and speeds calculated, so I'm curious about your setup. At the rate you're spraying, it would take you 128x80 seconds or 170 minutes to cover an acre. That just doesn't sound right.

4. ### RicLawnSite Fanaticfrom S W FloridaPosts: 11,956

While your math is fairly correct, you sure made it hard on your self.

Do your self a favor and make it simple on your self. Use 1,000 sq ft as your test plot to find your Gallons per thousand. Most all pesticides application rates are listed as 1,000 sq ft or an acre.

At you present calibration your 25 gal tank should do approx 10,200 sq ft. Therefore by simply reading a Label you can multiply the per thousand rate times 10.2 to find how much pesticide to add to your 25 gallon tank. BTW .75 oz of 2,4-D per thousand X 10.2 = 7.65 oz which is close enough because of rounding error.

Now another suggestion would be to reduce your Carrier rate from 2.46 to ONE gallon per thousand by changing to a smaller tip. Most Herbicide with work better at a Higher AI (concentration) per gallon.

.

5. ### shortgrass01LawnSite Memberfrom SCPosts: 160

Nate'sLawnCare

Hi, and thanks.

I tested with a single adjustable cone nozzle on a wand. I measured a spot on the road front, and walked the area fanning the wand back in forth covering the road evenly as possible. I did notice as it began to dry the heavy water marks looks snaked. I may need a different nozzle.

Atm That all I have to test with. I normally use this for roundup/spot spraying. But I was wondering if I could use this to put down 2,4-d blanket application.

Then I began trying to figure our the mix required.

6. ### Nate'sLawnCareLawnSite Bronze Memberfrom Nashville, NCPosts: 1,001

I also calibrate spray rate per 1000 square feet for easier calculation, but if your 25 gallon tank is only covering approx. 10,000 square feet, you'll have to refill 4 times per acre. That's not very productive.

Edit: I saw your response and it now makes sense. You definitely would be better off with a multi nozzle setup or switch over to an air inducted 110 degree single nozzle and spray without sweeping. Holding that nozzle 16 to 20 inches above the ground, at a normal walking pace, you should be able to cover 1000 square feet in approximately 2 minutes. You'll still have to calibrate by timing your 1000 square foot area, then capture the spray for that same time period. Good luck!

Last edited: Mar 4, 2013
7. ### RicLawnSite Fanaticfrom S W FloridaPosts: 11,956

Get rid of the adjustable nozzle and use a flat fixed fan for more accurate calibration.

.

Thanks Ric.

9. ### shortgrass01LawnSite Memberfrom SCPosts: 160

Thanks Nate

My math is 10,365 sqft per tank But I lose .5 gal at the bottom and have to refill.
104oz=.8125 gal
340ft x .8125g=10,365

Until I can get better equipment I am using this to cut down on dry product. Dry product getting way to high priced to use going forward.

I pretty much knew I may have to get a new Spray Gun, but was hopping I could get away with what I had..lol
I believe you guy tho, I fixing to order it now..Just have to figure out the my options Spray Gun and tips nozzles.

Thank alot...for me it gets confusing for at times.

10. ### Nate'sLawnCareLawnSite Bronze Memberfrom Nashville, NCPosts: 1,001

If your spray gun has a standard, I believe it's 5/8 inch cap to hold the nozzle on, you should be able to get a variety of nozzles to try. I'll attach a link to show the flow rates at different pressures, you'll need to run at least 30 psi. They usually are less than \$10 each and you can order them here:

http://www.paulbparts.com/search/content/teejet?filters=tid%3A28%20tid%3A207%20tid%3A35%20ss_cck_field_filter_material%3A%22stainless%20steel%22

Table with flow rates:

http://www.paulbparts.com/specs/aiSprayTips.html