You need to leave it at 4:1 setting. It gives you room to dilute it more for less soiled conditions, but if it's trashed carpet, you can go 4:1 and get the desired resultsFor the hydro force sprayers, is there any that allow you to go easily from 8:1 to 4:1? What’s industry standard for not having to mix yourself? 4:1?
When it's set at 8:1, it's harder to dilute it properly on the job, because you're using more powders and less water when you mix it. I've tried both and 4:1 is the best method