ΔE 10.0, fair: the same colour family, but not a straight swap. Light Turquois (Phthalo) is warmer than Hydra Turquoise.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Light Turquois (Phthalo) is warmer than Hydra Turquoise.
The same difference applies the other way round: Hydra Turquoise is cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Hydra Turquoise on the colour wheel See Light Turquois (Phthalo) on the colour wheel
All matches: Hydra Turquoise equivalents · Light Turquois (Phthalo) equivalents