In commercial centres, a float session usually lasts for fifty to sixty minutes. In sports training or therapy applications, float sessions are often shorter - thirty to forty minutes.
Longer sessions are popular with regular floaters.
My doctor has been telling me to go on a holiday, but I don't have the time. I treat my visits to the tank as mini-escapades. It is impossible to sink in a float tank. The tank solution is ten times more buoyant than seawater. The freedom of near-weightlessness is what feels best of all.