Total columnal electron content in the ionosphere over the magnetic equator during the postsunset hours is found to be greatly reduced on the nights with strong equatorial spread F conditions, as compared to that on nonspread F nights. The association of spread F and reduction of electron content over the magnetic equator is suggested to be due to the additional fountain generated on the nights when electric field continues eastward for a couple of hours even after sunset. ¿ American Geophysical Union 1990