Abstract: A mnemonic temperature marking system for fluid valves, especially of the type used in bathing vessels such as bathtubs and showers. Any user can easily, quickly, and accurately set the valve so that water of the desired temperature will flow when the valve is adjusted so that the marker is aligned with a pointing arrow on the valve. The marking system comprises a plurality of individual, personalized, or unique markers (16). Users of the bathing vessel adhere the markers to the valve (knob (14) or escutcheon (10)) at respective positions where such users' desired water temperature settings are adjacent the valve's fiducial marker (12). The markers can comprise graphic symbols (16', 26), letters (32), or markers (34) which can have a plurality of letters (for initials of a user) adhered.