What is the difference between upstream and downstream chemical injection?
Downstream injection introduces chemical after the pump on the high-pressure side, using a venturi injector that draws chemical into the water stream. The chemical never contacts pump internals, which protects pump seals. It works best with a wide, low-pressure nozzle (black soap tip) and delivers chemical at lower concentration. Upstream injection adds chemical before the pump on the inlet side, which allows chemical to be applied at full system pressure through any nozzle. Upstream requires chemical-compatible pump seals and is used when high-pressure chemical application is needed.
How do I know which detergent or chemical to use for my application?
Match the detergent type to the soil type. Alkaline (high pH) cleaners cut grease, oil, and organic soils - most vehicle wash soaps, degreasers, and general-purpose detergents are alkaline. Acid (low pH) cleaners dissolve mineral scale, rust, oxidation, and calcium deposits - aluminum brighteners, descalers, and concrete cleaners are typically acidic. Enzyme-based cleaners break down organic matter biologically and are used in some agricultural and food processing applications. When in doubt, ask Alkota or your chemical supplier for a recommendation based on your specific soil and surface type.
What is foam application and why is it used?
Foam application blends air into the chemical-and-water mixture to create a thick, clinging foam similar in consistency to shaving lather. Foam adheres to vertical surfaces much longer than liquid, giving the chemical more dwell time to penetrate and loosen soil before rinsing. This reduces chemical waste and improves cleaning effectiveness on vehicles, building exteriors, silos, and any vertical surface. A foam cannon or foaming nozzle accessory is required, and the chemical must be appropriate for foam use.
What is a two-step wash process?
Two-step washing uses two chemicals applied sequentially rather than a single detergent. Step 1 typically applies an acidic pre-soak that loosens mineral scale, oxidation, and road film. Step 2 applies an alkaline cleaner that neutralizes the acid and lifts organic soils. Together the two chemicals address a broader range of soils than either could alone. This process is popular in truck washing, fleet maintenance, and agricultural equipment cleaning where both mineral deposits and petroleum-based soils are present.
Are all cleaning chemicals safe to use with any pressure washer?
No. Some chemicals can degrade pump seals, O-rings, hoses, and other components. Solvents may dissolve rubber seals. Strong acids can attack pump metals and seals in equipment not rated for acid service. Always verify that any chemical you use is compatible with your machine's pump type, seal materials, hoses, and fittings before use. Alkota can advise on chemical compatibility for their equipment. When trying a new chemical, start conservatively and inspect seals and hoses for swelling, softening, or leaking.
What is a venturi injector and how does it draw chemical?
A venturi injector creates a pressure differential by accelerating water through a narrowed section of tubing. The resulting low-pressure zone draws chemical from a supply tube into the water stream through suction - no electric pump required. Venturi injectors are passive, reliable, and require no power. They draw chemical most efficiently when a wide (low-pressure) nozzle is used, because the pressure differential is greatest under lower back-pressure conditions. Switching to a high-pressure nozzle typically stops chemical injection.
Can I use bleach or sodium hypochlorite with my pressure washer?
Sodium hypochlorite (bleach) is commonly used in soft washing and some sanitation applications. However, bleach is corrosive and will damage pump seals, O-rings, and other components not designed for chemical service. If you plan to use bleach regularly, your equipment must be specifically rated or configured for sodium hypochlorite - many operators use a separate downstream injector and avoid running bleach through the pump entirely. Always flush the system thoroughly with clean water after any bleach application to prevent corrosion.
What is a quaternary disinfectant and when is it used?
A quaternary disinfectant (quat) is derived from ammonium and is used for sanitizing and disinfecting surfaces in food processing, healthcare, agriculture, and animal husbandry. Quats are effective against bacteria, viruses, and fungi. They are commonly used through downstream injection after pressure washing to sanitize equipment and surfaces. Always follow label dilution rates and contact time requirements, and verify that the product is approved for your specific application and surface type.