A student prepares a simple tube sampler to provide an integrated water column sample from Lake Powell (Utah & Arizona, USA). The weighted, flexible tube is lowered through the water column, entrapping a vertical cylinder of water. By crimping the top of the tube and creating a vacuum, the 10-m deep tube can be brought to the surface and emptied into a container to provide an integrated water sample of the epilimnion. Here, sampling was being done in the upper reaches of Lake Powell where the turbid water brought in by the Colorado River is still evident.