Depends on what your doing and your horsepower. if you are doing sidewalks and you can keep your pressure up around 3000 psi go 8 gpm, if not then stick with the 5.5 gpm. If you are doing mainly residential 2500 psi is usually plenty and 8 gpm is the way to go.
So I'm back in the neighborhood (7 months later) where I cleaned the driveway shown above. The striping (banding) looks much, much worse now. I've adopted the pre/post treatment method since then, but this just looks bad. I'm thinking I'll go back and re-do the driveway for free (treating it this time). The pattern really confuses me too. I overlap every pass to ensure I'm getting a good clean, but this happens.
Could this be a PSI or GPM issue?
So I'm back in the neighborhood (7 months later) where I cleaned the driveway shown above. The striping (banding) looks much, much worse now. I've adopted the pre/post treatment method since then, but this just looks bad. I'm thinking I'll go back and re-do the driveway for free (treating it this time). The pattern really confuses me too. I overlap every pass to ensure I'm getting a good clean, but this happens.
Could this be a PSI or GPM issue?