Could we use INTERVAL for the datatype instead? 

"""
'breakpad=# insert into junk values('10000.1'); 
INSERT 0 1
breakpad=# insert into junk2 values('10000.1'); 
INSERT 0 1
breakpad=# select * from junk;  
  blah   
---------
 10000.1
(1 row)

breakpad=# select * from junk2; 
    blah    
------------
 02:46:40.1
(1 row)
"""

Default for INTERVAL is to accept input as seconds.  Format is documented here: 
http://www.postgresql.org/docs/9.3/static/datatype-datetime.html#DATATYPE-INTERVAL-INPUT