Children taken ill from a Northampton pool were suffering from an "adverse reaction" to high levels of chlorine, gym bosses have said.
The Virgin Active gym in Riverside Retail Park closed its pool on Thursday after five children complained of breathlessness and sickness.
Gym bosses said a system fault resulted in a higher than normal chlorine concentration entering the pool.
The children are recovering at home and an investigation is under way.
The pool reopened on Friday.
A spokesperson for Virgin Active said: "A system fault resulted in a small amount of water, with a higher than normal chlorine concentration, entering the pool.
"Five children close to the point of entry of that water suffered an adverse reaction.
"The pool, which was closed following the incident, is now safe and was reopened."
- Published17 February 2012