I added some code to a previously work FORTRAN program but with the addition of these few lines it now does not work, but I can't see anything wrong with the code. Can someone else take a look and see if the strcutre is correct? It does compile OK.

Code:
t_1=(x_salt)**2
        t_2=-0.1083*t_1
        t_3=1.244*x_salt
        t_4=-4.694e-8
        t_5=x_salt+0.1353
        t_6=(t_2+t_3+t_4)
        t_7=t_6/t_5
        if (sor1.gt.sor2) then 
	 t_8=(sor1-sor2)
	 sor=(t_7*t_8)+sor1
        else
         t_8=(sor2-sor1)
         sor=(t_7*t_8)+sor2 
        endif