Did you dilute the soap in the tank with water. I have low pressure too and I got mine to work well by taking my soap (which recommends 1oz per gallon) and mixing it 3:1 with water in the jug and then setting the slide to the 4:1 ratio. It seems the product was too thick by it's self for my low pressure. I think it was SpoiledMan that suggested this solution or maybe Setec...can't remember for sure. You're still only using 1oz of soap per gallon at this ratio so it's not wasteful.