The tank supports are 120° apart. When my tank is fully screwed down, part of the face is covered. Rotating the base 180° will not center the face, but cause it to be partially covered on the other side.I just took the base off my Zeus to inspect the coil and when I put it back together the face was not centered. So I took the base off again and rotated it 180° and it fixed it. Perfectly centered.