Downstream injectors introduce the cleaning chemical into the water stream after or downstream of the pump. Care must be taken to size the injector to the system volume or GPM. Check your manufacturer’s owners manual. Too small of an injector causes a large pressure drop across the injector and injects a very high concentration of chemical. Too large of an injector will not draw any chemical. Downstream injectors require low pressure, generally about 200 PSI, to activate the chemical flow. A double nozzle holder, rollover nozzle, and a double lance are a few accessories that allow mounting a low pressure spray tip, as well as the standard high pressure spray tip. An adjustable nozzle allows a large orifice to be opened around the high pressure spray tip.
Good customer services 
