Dwell time beats pressure
Detergent is what lets you drop the pressure, and dropping the pressure is what protects the surface. We cover snow foams for vehicles, patio and stone treatments that work on algae over days rather than seconds, degreasers, and wood cleaners — with dilution ratios and the surfaces each one attacks.
The detergent that lets you drop the pressure — which is what protects the surface.
A bottle that clips into the machine — no measuring, no mixing, and no choice of dilution.
An alkaline product eats a bare aluminium wheel and dulls a composite deck. The stated pH and the surfaces it warns against are what avoid an expensive repair.
Kärcher 3-in-1 Stone Plug 'n' Clean
A product that is too thick blocks the injector, and one not meant for it attacks the pump seals. Stated compatibility with detergent suction is decisive.
Kärcher RM 611 Stone & Facade Cleaner
It is inadvisable. It foams heavily without being designed for these machines, leaves a film and, on a car, strips the protection. There is no gain over a suitable product.
Only at low pressure, via the built-in tank or a foam cannon. At high pressure the injector draws nothing: that is the most common cause of "my product will not come out".
Yes, a pre-rinse removes the bulk and lets the product work on what is genuinely ingrained. Applied to a dry, dirty surface, it is absorbed and loses its effect.
For the stated time, and never until it dries. A product that dries on the surface leaves marks far harder to remove than the original dirt.
Alkaline moss-killers are. Wetting the vegetation at the foot of the wall before and after application dilutes the run-off and limits the damage.
A pH-neutral shampoo, yes, if you want to keep a wax or a treatment. A generic degreaser cleans very well and takes the protection off with the dirt.
A product not intended for pressure washers can attack the injector seals. Rinsing the circuit by drawing clean water after use markedly extends its life.
Concentrates last two years sealed, less once opened and left to freeze. A can that has frozen separates into layers and no longer emulsifies: the stated shelf life means something here.
The product works through dwell time, not through pressure, and overdosing does more harm than good. An all-purpose concentrate correctly dosed and a neutral shampoo for the car cover the essentials — and rinsing the circuit after use avoids injector failure.