A well treatment additive includes a siloxane surfactant, a solvent and an aqueous phase. A variable capacitive device having a fixed vertically-inclined silicon-bearing compound electrode and a movable vertically-inclined silicon-bearing compound electrode produced by arranging a sacrificial layer on a base silicon-bearing compound electrode, depositing a grown silicon-bearing compound electrode on the sacrificial layer, and etching the sacrificial layer. By contrast, when the pressure of water column in the water inlet is greater than that of the water outlet, the retaining element is moved to the first position to drain water. The bird house is shaped by shaping pieces, such as flat shape retaining pieces, held in or by the collapsible shell or by a shaping frame that fits into the collapsible shell. In the second position, the hood uncovers the rear side of the basin, whereby the operator can perform operations from the rear side of the basin without the hood interfering.