No, both Sephardi and Ashkenazi women must count seven clean days.
However, different Sephardi communities have different practices with respect to the five day minimum before the clean days. You should consult your Rabbi to determine which practice to follow.
- Some Sephardi communities mandate a full five days from the onset of niddah.
- Some require only four days from the onset of niddah.
- In some communities, a woman counts a four-day minimum from the last intercourse prior to niddah rather than from the onset of niddah. Furthermore, according to this custom, a woman who douched thoroughly following intercourse does not need to wait any minimum days, but can begin the seven clean days as soon as a hefsek taharah is possible – even after a one day flow which was preceded by intercourse the night before.
- Some communities count from the last intercourse only when a woman became niddah from a stain, but count from the onset of niddah if she had a flow of blood.