A fluid treatment element comprises a fluid treatment pack including a fluid treatment medium. The fluid treatment pack has a hollow interior and a barrier is disposed in the hollow interior. The barrier separates a blind region in which fluid cannot flow between the hollow interior and the fluid treatment pack from an open region in which fluid can flow between the hollow interior and the fluid treatment pack and prevents fluid from flowing between the blind region and the open region. The fluid treatment pack also has an end region having a sealed end. The fluid treatment element defines a flow path for process fluid to be treated passing in a lengthwise direction through a portion of the fluid treatment pack.