I am planning on applying my herbicides out of a 4 gallon backpack this year. I am wondering if anyone has info or ideas for a containment area to be able to fill on site (out of truck bed or open trailer). I am envisioning a 25 gal supply tank (water only), a 25 gal containment pan, and a way to pick up or empty the pan in case of a spill. I do extremely small yards hence the backpack. Has anyone built one of these or had to get one approved by their state? Any help or ideas would be appreciated.