Ethel Powell, 74, has lived in the Presidential Gardens, a middle-income apartment complex in the Arlandria section of Alexandria, for 24 years, but like many of the other 600 tenants there, she's not sure how long she can stay.

The apartment complex, owned by several members of the Hechinger family and assessed by the city at almost $8 million, is being sold, Dan Russell, the director of management for the Presidential Gardens, said yesterday. He said a group of private investors known as Salisbury Slye Ltd. is expected to take over the 21-building complex next month.

Russell would not comment on the selling price, where the new owners are based, or if they intend to turn the buildings into condominiums.

When the sale goes through, he said, the names of the new owners will be announced.

John Hechinger Jr., whose grandfather built the apartments in 1942, said he sold them because he "thought it was the right thing to do" and that he was unaware of the new owners' development plans.

"If they put the rent up to $500 of $600, my sister and I will have to go," said Powell. "I am trying not to worry. When you are my age, you live day by day. But I don't know where we'd go."

If the apartments are converted to condominiums, city law requires that tenants be notified at least 120 days in advance, said Beverly Steele, from the Alexandria Housing Office.

Developers also are required by law "to set aside up to 20 percent of the units for three years to the elderly and handicapped presently in the buildings." But if it converts, Steele said, "the reality is everybody cannot stay."

Thirty other tenants, upset that they were never contacted about the new ownership and alarmed that they may be displaced, met Tuesday night to discuss the sale. Phyllis Carp, the organizer of a newly formed tenant group at the complex, said she was worried that the new owners would not preserve the apartments in their present form, which she called the "prototype of all garden apartments." In addition, she said, if they are renovated, the cost would force out many tenants.

Most of the 391 units are single bedroom and cost between $350 and $400 a month, according to the resident manager, Mavis Derflinger.

"Where are we going to go? We would have to move way out to find something we could afford," said Carp. "We don't want to go to Reston or anywhere else and there are no places left in Alexandria."

Only 1 percent of the multi-family rental units in Alexandria are vacant, said Mark Looney, the director of Alexandria's Landlord Tenant Relations Office. Looney said that Arlandria, easily accessible to Rte. 1 and Crystal City, is ripe for development and that many other properties near the Presidential Gardens are likely to be sold soon.

Tom Ross, a community coordinator for the Tenant Organizing Project, a Northern Virginia non-profit group that advises tenants, said that until the new owners make themselves known, the tenants plan to "get together to more effectively express their concerns." He said Alexandria was quickly becoming a city "of the very rich and very poor" and "these middle-class people want a chance to stay."

When the new owners are announced next month, Carp said she plans to meet with them "to work out a preservation and nondisplacement plan."