Color cells by conditional formatting

[#1]

I need a script that looks through all columns and color cells with the value "< LOD". My script does not give the desired outcome. Any advice?

dt = Current Data Table();

// Get all of the column names in the data table
ColNames = dt << get column names( string );
NRows = N Rows( dt );

// Loop through each column and row to find "< LOD" and color the previous cell
For( i = 1, i <= N Items( ColNames ), i++,
	column = Column( dt, ColNames[i] );
	For( j = 2, j <= NRows, j++, // Start at row 2 to avoid coloring out-of-bound cells
		If( Row(j) == "< LOD",
			column << Color Cells( j - 1, "Red" );
		)
	);
);

[#2]

Other and more elegant solutions are more than welcome!

[#3 · Accepted solution]

This looks for value "F" but most likely gives some ideas what you could change (get all rows beforehand for each column, color cells argument ordering, ...)

Names Default To Here(1); 

dt = Open("$SAMPLE_DATA/Big Class.jmp");

colnames = dt << get column names(character, string);

For Each({colname}, colnames,
	r = Loc(dt[0, colname], "F");
	If(N Items(r) > 0,
		Column(dt, colname) << Color Cells("Red", r);
	);
);

Write();

Edit: Removed unnecessary Show(r); from the loop