In the past I have been using my homemade "skid" type unit with two 50 gallon tanks, 1 pump and 1 hose reel. I love this unit! I can carry 100 gallons of water to tender my PG or I can carry 50 gallons of water and use the other tank for insecticide (trees and perimeter pest) and then pump over more water as needed etc. The only thing I wanted to add was a little tank (20 gallon) so I can spray broadleaves if needed on hills or hard to get areas. I came up with a system where I can still run my two 50 gallon tanks, but I can now also transfer water over to my 20 gallon tank and spray broadleaves which will have its own dedicated pump and hose reel also. I had to order a custom 20 gal tank to make it fit well. The broadleaf system will be totally seperate so once in the tank it will have no way to get to the two 50 gallon tanks. It is really a very simple design, but just wanted to share with you guys! I am pretty proud of it and can't wait to use it. We just finished the aluminum work...and all I have to do is plumb it up and put the hose on the reels! Here are some pics! The last two pics are of my old unit and you can see how the plumbing is setup to transfer.