Is what the questioner did correct, namely her performing ghusl after seeing light blood discharge following the cessation of menstruation, and then ignoring the subsequent light bloody discharge and turbidity, relying on the Hadith: "We did not consider yellowness and turbidity after purity to be anything," and her husband having intercourse with her?

A woman's ghusl (definition) (ritual bath) at dawn is valid if she sees dryness (one of the two signs of purity). Any blood she sees after that, if it occurs during a time suitable for menstruation, is considered menstruation, even if it is outside her usual time. However, if it is a yellowish or brownish discharge after achieving purity, it is not considered menstruation.