Blue Flux vs Joridyn Turquoise

How close are they?

ΔE 19.7, loose: different enough that you should pick on purpose. Joridyn Turquoise is noticeably darker, more muted, cooler than Blue Flux.

Can I use Joridyn Turquoise instead of Blue Flux?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Joridyn Turquoise is noticeably darker, more muted, cooler than Blue Flux.

Can I use Blue Flux instead of Joridyn Turquoise?

The same difference applies the other way round: Blue Flux is noticeably lighter, more saturated, 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.