ΔE 26.0, loose: different enough that you should pick on purpose. Light Sea Blue is a little lighter, cooler than Smalt Hue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Light Sea Blue is a little lighter, cooler than Smalt Hue.
The same difference applies the other way round: Smalt Hue is a little darker, warmer.
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 Smalt Hue on the colour wheel See Light Sea Blue on the colour wheel
All matches: Smalt Hue equivalents · Light Sea Blue equivalents