Rhodium Bath

Hi Orchidians, How can one possibly identify that the Rhodium Plating
Bath is not up to that level (strength) that it was when one has
started it?

Is there a convenient and practical way to identify its strength
(density) please, any help? I am noticing that its bath is not that
brilliant as it used to be after one and a half years using it.

JT Malta.

What is typically recommended for small baths is to draw and save a
small sample vial from a fresh new batch. Use another same size vial
with a sample from the used bath and visually compare against the
solution as it is used. It becomes lighter in color as it is used.
Replenish as needed from concentrate syrup to achieve corresponding
color.