How should red-violet be balanced if it contains excessive red?

Correct answer: By increasing violet

The governing concept is balancing the two components of a tertiary colour. Red-violet requires red and violet in a suitable relative proportion. When red is excessive, gradually adding a small amount of violet strengthens the other named component and moves the mixture back toward red-violet. Increasing green or yellow introduces unrelated components, while adding blue could push the hue toward blue-violet rather than correct it precisely.