I just hooked up dual pumps for my portable sprayer. What a difference. I was having trouble with the pressure switch on my 2.1gpm 60psi pump, so I ordered another pump (shurflo 1.8gpm 60psi). I also ordered a new pressure switch for my old pump. This was all before i found this board and all the great info. Actually I think I ordered the shurflo about 2 days before I found out about the delevan. Its funny because after I started using the 2.1 gpm pump to do roofs, I swore I would never take a pump up sprayer on a roof again. Now that I have the dual set up I'll not want to go back to a single pump. When these bite the dust, I guess I'll buy one or two delevans. I have this sprayer set up so that I can place the intakes in my not so huge 35 gallon chemical tank, which is enough to do at least one roof. If I can't get my trailer close enough to the house I can just wheel the dolly around where ever I need it and pump out of a 5 gallon jug. This sprayer is also great for spraying stripper and brightener on decks. The battery and a small charger are mounted on the back so it can be easily charged after the job by just plugging it in when I put the trailer back in my garage.