Biofilm removal from stainless steel vials in the DBA instrument during pulsed cathodically weighted polarization (P2). The biofilms were grown from inocula of D. geothermalis in 8.5 ml medium for 24 h as described for Fig. 2. The vials were then emptied, rinsed, and refilled with 20.5 ml medium and polarized (or not) for 4 h, 24 h, or 48 h. The columns show the summed amount of biofilms per vial and the error bars (n is given in parenthesis). Significant difference is indicated P < 0.05 **