I would treat them for at least five days, probably a little longer--ich is only susceptible to meds during it's freeswimming stage, and you could have little babies getting ready to hatch , and if the meds are gone, they can swim right back onto your fish--i never treat ich for less than a week--usually more--but i am a little paranoid--but I have very healthy fishes! if your temp has consistently been at 85, you could probably get by with five days...vacuum your gravel really well....