Anyone with easy access to the 1900 soundex:
I'm looking for the names Schardt and Otten, most likely to be found in Cincinnati.

Scott,
The NARA Soundex for Schardt is S630, for Otten is O350.
Using your spelling in a 1900 Census index for Cincinnati, Hamilton County, there are 6 listings for Schardt & 7 listings for Otten.
Schardt:
Aug in ward 14, Fred ward 10, Fred ward 6, Jessie T. ward 14, Louis ward 14, & Mary ward 13.
Otten:
Bernard ward 3, Charles ward 19, Henry ward 3, Joseph ward 21, Joseph E. ward 21, Otto B. ward 10, William ward 12.
Hope this helps.

I have family member Anna Otten Father Bernard Otten. They lived in Hamilton.Cinncinatti,Ohio.She was born 1858.

Interesting. I see an Anna Otten, daughter of Bernard and Maria age 9 in the 1860 Hamilton OH census. Is that your Anna? Can you tell me anything more about your Anna Otten?

The Ottens I've been researching are Bernard/Barnhard Otten + Katherine Geiger. They married in 1872, lived in Franklin county IN; children Anna, Margaret, and Herman. Herman and Margaret (married Louis Schardt) lived in Cincinnati as adults.
My Bernard was born in Bavaria about 1835 (according to the 1880 census; 1900 has him born in Indiana of German parents). I've had no luck positively locating him in any records prior to his 1872 marriage. It's possible his name was Bernard Henry or Henry Bernard or that he had a brother named Henry -- an infant Otten named Henry died in Franklin county IN in 1880.
With so few Ottens in the area, and Bernard a relatively uncommon given name, perhaps there's some connection between your Bernard and mine, I just don't know what it is.
A tantalizing item is the 1850 census showing a Henry and Getzina Otten in Cincinnati with children named Bernard and Henry and another Bernard "Notten" next door -- no proof that these are related to either my or your Bernard.

There are a lot of Otten in the Springgove cemetery.
www.springgrove.org