RM}First, I am looking for an undergravel filter that used to have an 
irstone
RM}along the entire length of the back built in.
That sounds like the Penn Plax Undercurrent u/g filter.  I have one for
a 29 gal tank, although it isn't currently set up. :-(
--- PCBoard (R) v15.3 (OS/2) 10
---------------