In an electrolytic apparatus for removing contaminants from water, a set (110) of spaced apart conductive electrodes (40) in a reaction chamber (54, 112, 114), is arranged in oppositely charged groups of first and second interleaved electrodes with flow paths between them. Non-conductive turbulence inducers (158, 168) on the faces of electrodes (40) are applied to water in the flow paths. One variety is modular elements (1 58) with stepped increases in width to present a narrow leading edge in the direction of flow. Another variety is a continuous set of wave guides (168) bordering the flow path. Electrodes (40) are selectively powered in patterns creating turbulence, with effective patterns including a first and last electrode powering pattern and a mini-cell electrode powering pattern.