Abstract: A chlorinator of the floating type includes a cannister (1) having oppositely disposed side walls (3 and 4) and a pair of oppositely disposed end walls (5 and 6) is provided with coupling means in the form of ribs (21) disposed on the outer surfaces of the end walls and float means (2) having a central aperture (13) therein whose axis is vertical includes a generally circular central part (13, 14) and a pair of diametrically opposed segments (15 and 16) each of which includes a peripheral part (15a and 16a) each of which in turn includes clearance portions and coupling portions on which a plurality of coupling ribs are formed so that the cannister may be inserted into the aperture formed in the float means with its coupling means adjacent the clearance portions and which then may be rotated about its vertical axis to cause its coupling ribs to engage the coupling ribs (17 and 20) formed on the peripheral portions (15a and 16a) of the segments (15 and 16), an inwardly projecting protrusion (11, 12) is provided