A cell (100, 200, 500) for ozonation of water comprising, a cathode (102, 204, 504) and an anode (106, 202, 502), separated by a membrane (104, 206, 506), the anode (106, 202, 502) and cathode (102, 204, 504) each have an array of holes to allow water to flow through to the membrane(104,206, 506); a housing enclosing the cell (100, 200, 500) and having a cathode housing portion and an anode housing portion separated by the membrane(104, 206, 506), the cathode housing portion having a first inlet and a first outlet though which a first flow path is formed therebetween configured to allow water to flow across the cathode (102, 204, 504) and the anode housing portion comprising a second inlet and a second outlet through which a second flow path is formed therebetween configured to allow water to flow across the anode (106, 202, 502) to produce ozonated water flowing from the anode and further configured to allow at least some of the ozonated water from the second flow path to flow through an ozone concentration detector integrated within the housing and return to the second flow path; wherein the cathode housing portion encapsulates the cathode (102, 204, 504), and the anode housing portion encapsulates the anode(106, 202, 502) and the ozone concentration detector is a spectrophotometer (560, 570) and; first and second input ports and first and second output ports are inlet and outlet ports coupled to the first and second inlets and first and second outlets, respectively, of the housing to allow water to flow separately through both portions of the housing, wherein the cell (100, 200, 500) comprises a bubble trap (562,762) to remove bubbles from the ozonated water that flows through the ozone detector and the bubble trap (562, 762) comprises a chamber including flow baffles (588, 589) which slow and widen flow of the ozonated water through the chamber. a cathode (102, 204, 504) and an anode (106, 202, 502), separated by a membrane (104, 206, 506), the anode (106, 202, 502) and cathode (102, 204, 504) each have an array of holes to allow water to flow through to the membrane(104,206, 506); a housing enclosing the cell (100, 200, 500) and having a cathode housing portion and an anode housing portion separated by the membrane(104, 206, 506), the cathode housing portion having a first inlet and a first outlet though which a first flow path is formed therebetween configured to allow water to flow across the cathode (102, 204, 504) and the anode housing portion comprising a second inlet and a second outlet through which a second flow path is formed therebetween configured to allow water to flow across the anode (106, 202, 502) to produce ozonated water flowing from the anode and further configured to allow at least some of the ozonated water from the second flow path to flow through an ozone concentration detector integrated within the housing and return to the second flow path; wherein the cathode housing portion encapsulates the cathode (102, 204, 504), and the anode housing portion encapsulates the anode(106, 202, 502) and the ozone concentration detector is a spectrophotometer (560, 570) and; first and second input ports and first and second output ports are inlet and outlet ports coupled to the first and second inlets and first and second outlets, respectively, of the housing to allow water to flow separately through both portions of the housing, wherein the cell (100, 200, 500) comprises a bubble trap (562,762) to remove bubbles from the ozonated water that flows through the ozone detector and the bubble trap (562, 762) comprises a chamber including flow baffles (588, 589) which slow and widen flow of the ozonated water through the chamber.