A public pool in Hastings is being investigated after an outbreak of vomiting by students using it.
About 20 students from Taradale High School became sick at the Frimley Pool at 10am this morning, during a swimming sports day.
Many other students reported feeling unwell, although they were recovering by the afternoon.
A spokeswoman for the Hasting District Council said the pool had been closed and was now being investigated by the council and Public Health Unit.
She said chlorine tests carried out over the day found the levels to be normal, and more testing was now being done by a commercial agency.
"Initial results from those tests are expected [tomorrow] with comprehensive results expected by Saturday."
The council's pool manager, Alice Heather, said she expected the pool to reopen on Saturday.
About 350 children were using the pool on the day and there have been no other reports of sickness this week, the council said.
A triathlon due to be held at the pool tomorrow is now likely to be reduced to a duathlon or postponed.