That product is a joke, watch the video and the guy is UNSAFELY PRESSURE WASHING A SHINGLE ROOF.
The product is like Oxyclean which does not remove the fungus, thus the guy with the pressure washer blasting the fungus and granules off the roof.
This kind of damage to people's property is discouraged.
That pump will not hold up with a lot of chemicals like SH, acids and caustics.
What will the chemical be that you were thinking about buying this weak chemical pump for?