Originally Posted by RigglePLC
The Hypro roller pump may be a bit small for your purpose. With most pump sales information...they are optimistic. You can usually get high volume or high pressure, but not both at once. I am not sure a roller pump is suited for wettable powders.
Remember that to use a second tank--you need a valve on the suction side--and another valve on the feed back line from the pressure regulator valve, (which is commonly also used for agitation). You don't want the two tanks to mix their ingredients. You definitely do not want any chance of applying a herbicide contaminated mix to trees...high risk.
I'm hoping the 4-roller pump will get me by until I see how next year is going to turn out. After the drought in my area I'm a little skeptical on dropping $1000 for a Honda/D30. I'm thinking about chopping my 300ft of 1/2 hose down to 150ft also. I prefer 2 gallons of mix per 1000 sq ft when applying my pre and post. Once I get everything mounted and plumbed I'll go out and calibrate with the 300ft and see how it performs. I just mark off 1000 sq ft of concrete, spray it with water while someone times me with a stop watch, then I take a 5 gallon bucket marked in 1 gallon increments and hold my gun in it for the same amount of time it took me to spray the 1000 sq ft. If I'm under 2 gallons or over 2 gallons I adjust my pressure accordingly. That's the way I do it. If I have to switch my application rate to 1 gallon per 1000 sq ft that's no biggie. I've just always preferred 2. I'm looking to contruct a walking boom this Winter also. Any suggestions or advice on that is welcome.