Corrosion inhibitor in hot water?

[phebas]

Is there a way to test if the bitter taste in water from an indirect hot water cylinder (via rinsing after teeth cleaning- everybody does it) contains corrision inhibitor, e.g. due to a small hole(s) in the coil in the cylinder?

[stoneyboy]

phebas,
Buy some blue food dye and add it to the heating system.
end

[phebas]

great idea,
many thanks