You could absolutely use this chemical injector for your task, however, you will have to worry about the chlorine bleach drying out your hose and gun o-rings. This injector attaches to the discharge outlet on your pump, then your hose connects to it.
We carry a high pressure soap injector that can be attached at the end of the wand which would prevent any damage to your hose and gun. I'm posting a link below to the product I am referring to for you to look at:
General Pump Soap Shooter Nozzle