are indicated by the arrows 18 in fig2 are not so rigidly supported in some instances these portions 18 of the molded plastic saddles have after a period of time in use become warped to such an extent that the seal between the periphery of the dome is not sufficiently tight against gasket 15 in its seat on the saddle mounting such that air pressure within the dome has been allowed to escape in the form of large bubbles that do not serve to efficiently aerate the liquid in the tank to cure this defect in the use of molded plastic saddles that ultimately show signs of warpage the herein disclosed clamping bar is provided this bar is a rigid stainless steel construction 20 one of which is adapted to be attached to the each of the individual warped domes mounted on the bottom of the aeration tank the clamp bar is shaped to be engaged over the top of the dome by the bolt 16 that holds the dome sealed tightly against the seal 15 in its seat on the saddle the bolt supporting the clamp bar in a position to extend diametrically across over the top of the.