Make sure you have the strainer on the pick up tube. Preheat your solution line by spraying water threw your hydrofoce sprayer while it's empty. Once hot Put the powder in the hydrofoce and spray into the hydroforce jug moving,the wand around to get the super hot tm solution to dissolve the prespray. A Good prespray with good ingredients will dissolve 100%
Some presprays aren't compatible with each other. Make sure you're cleaning all the old solution out of the hydro-force before adding a different solution I have that issue every now and then when I mix a liquid prespray with a powder.