why most three part nutrients are green , red , and orange?

I'm curious to know why most three part nutrients are green , red , and orange . I know chelate iron would definitely give some colour ,
but the some part should have no colour . So my Question is why is it green ,red , and orange . Do they put in Dye or some substances turn them into those colour , and if it is dyed what kind of dye has been used?

Marketing. Don't know what dye they use but pre Hawthorne GH I was told they used some pretty high quality dyes other wise the dyes would break down after some time.

AquaTerra said:

Marketing. Don't know what dye they use but pre Hawthorne GH I was told they used some pretty high quality dyes other wise the dyes would break down after some time.

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Thank you !